time varying corrections in x2sys_datalist

I have been experimenting with x2sys_datalist. I have gotten the program to correct data based on crossover errors estimated in x2sys_solve using -Ec (DC shift) and -Ed (DC plus a linear drift along the track) options. Using the -Et option (DC shift plus linear drift as a function of time along track), x2sys_solve seems to produce good results in the file *corrections.txt, but fails in x2sys_datalist

The script I am using, edited to eliminate some extraneous stuff is;

set TAG = $1
set plotname = $2

gmt set TIME_SYSTEM UNIX

set allcoas = $TAG/crossover-files/coa.all.txt

gmt x2sys_list -Cgrav -T$TAG $allcoas -E -FTcn -Vl > $TAG/grav.coe.txt

gmt x2sys_report $TAG/$TAG.coe.txt -Cgrav -T$TAG -Vl > $TAG/grav_report.txt

gmt x2sys_solve $TAG/grav.coe.txt -T$TAG -Cgrav -Et -Vl > $TAG/"$TAG"."$plotname"_corrections.txt

gmt x2sys_datalist =$TAG/$TAG.lis -E -L$TAG/"$TAG"."$plotname"_corrections.txt -T$TAG -Vl > $TAG/$TAG.$plotname.corrected.grav.txt

The output from the execution;

BEGIN
x2sys_list [INFORMATION]: Read crossover database from AIRBORNE/crossover-files/coa.all.txt...
x2sys_list [INFORMATION]: Found 75 pairs and a total of 35366 crossover records.
x2sys_list [INFORMATION]: Writing Data Table to Standard Output stream
x2sys_list [INFORMATION]: Crossovers from AN01 minus AN01 [461].
x2sys_list [INFORMATION]: Crossovers from AN01 minus AN02 [13].
x2sys_list [INFORMATION]: Crossovers from AN01 minus AN07 [247].
x2sys_list [INFORMATION]: Crossovers from AN01 minus AN08 [77].
x2sys_list [INFORMATION]: Crossovers from AN01 minus AN09 [133].
x2sys_list [INFORMATION]: Crossovers from AN01 minus AS01 [13].
x2sys_list [INFORMATION]: Crossovers from AN01 minus AS02 [142].
x2sys_list [INFORMATION]: Crossovers from AN01 minus AS03 [45].
x2sys_list [INFORMATION]: Crossovers from AN01 minus IB-2011 [12].
x2sys_list [INFORMATION]: Crossovers from AN01 minus IB-2012 [92].
x2sys_list [INFORMATION]: Crossovers from AN02 minus AN03 [11].
x2sys_list [INFORMATION]: Crossovers from AN02 minus AN07 [26].
x2sys_list [INFORMATION]: Crossovers from AN02 minus AS03 [1].
x2sys_list [INFORMATION]: Crossovers from AN02 minus IB-2011 [56].
x2sys_list [INFORMATION]: Crossovers from AN02 minus IB-2012 [78].
x2sys_list [INFORMATION]: Crossovers from AN03 minus AN03 [34].
x2sys_list [INFORMATION]: Crossovers from AN03 minus AN04 [1].
x2sys_list [INFORMATION]: Crossovers from AN03 minus AN05 [6].
x2sys_list [INFORMATION]: Crossovers from AN03 minus AS03 [16].
x2sys_list [INFORMATION]: Crossovers from AN03 minus IB-2011 [2].
x2sys_list [INFORMATION]: Crossovers from AN03 minus IB-2012 [2].
x2sys_list [INFORMATION]: Crossovers from AN04 minus AN05 [43].
x2sys_list [INFORMATION]: Crossovers from AN04 minus AS03 [1].
x2sys_list [INFORMATION]: Crossovers from AN04 minus AS04 [18].
x2sys_list [INFORMATION]: Crossovers from AN05 minus AN05 [225].
x2sys_list [INFORMATION]: Crossovers from AN05 minus AN06 [16].
x2sys_list [INFORMATION]: Crossovers from AN05 minus AN07 [42].
x2sys_list [INFORMATION]: Crossovers from AN05 minus IB-2011 [57].
x2sys_list [INFORMATION]: Crossovers from AN05 minus IB-2012 [109].
x2sys_list [INFORMATION]: Crossovers from AN06 minus AN06 [147].
x2sys_list [INFORMATION]: Crossovers from AN06 minus AN07 [176].
x2sys_list [INFORMATION]: Crossovers from AN06 minus AN08 [69].
x2sys_list [INFORMATION]: Crossovers from AN06 minus IB-2011 [32].
x2sys_list [INFORMATION]: Crossovers from AN06 minus IB-2012 [85].
x2sys_list [INFORMATION]: Crossovers from AN07 minus AN07 [164].
x2sys_list [INFORMATION]: Crossovers from AN07 minus AN08 [76].
x2sys_list [INFORMATION]: Crossovers from AN07 minus AS02 [2].
x2sys_list [INFORMATION]: Crossovers from AN07 minus IB-2011 [26].
x2sys_list [INFORMATION]: Crossovers from AN07 minus IB-2012 [87].
x2sys_list [INFORMATION]: Crossovers from AN08 minus AN08 [245].
x2sys_list [INFORMATION]: Crossovers from AN08 minus AN09 [20].
x2sys_list [INFORMATION]: Crossovers from AN08 minus IB-2012 [98].
x2sys_list [INFORMATION]: Crossovers from AN09 minus AN09 [425].
x2sys_list [INFORMATION]: Crossovers from AN09 minus AS02 [41].
x2sys_list [INFORMATION]: Crossovers from AN09 minus AS06 [380].
x2sys_list [INFORMATION]: Crossovers from AS01 minus AS01 [254].
x2sys_list [INFORMATION]: Crossovers from AS01 minus AS02 [253].
x2sys_list [INFORMATION]: Crossovers from AS01 minus AS03 [117].
x2sys_list [INFORMATION]: Crossovers from AS01 minus AS06 [247].
x2sys_list [INFORMATION]: Crossovers from AS01 minus AS07 [143].
x2sys_list [INFORMATION]: Crossovers from AS01 minus AS08 [67].
x2sys_list [INFORMATION]: Crossovers from AS02 minus AS02 [178].
x2sys_list [INFORMATION]: Crossovers from AS02 minus AS03 [8].
x2sys_list [INFORMATION]: Crossovers from AS02 minus AS06 [27].
x2sys_list [INFORMATION]: Crossovers from AS02 minus IB-2012 [1].
x2sys_list [INFORMATION]: Crossovers from AS03 minus AS04 [148].
x2sys_list [INFORMATION]: Crossovers from AS04 minus AS04 [414].
x2sys_list [INFORMATION]: Crossovers from AS04 minus AS05 [16].
x2sys_list [INFORMATION]: Crossovers from AS04 minus AS07 [4].
x2sys_list [INFORMATION]: Crossovers from AS05 minus AS05 [250].
x2sys_list [INFORMATION]: Crossovers from AS06 minus AS06 [326].
x2sys_list [INFORMATION]: Crossovers from AS06 minus AS07 [58].
x2sys_list [INFORMATION]: Crossovers from AS06 minus AS08 [258].
x2sys_list [INFORMATION]: Crossovers from AS06 minus AS09 [2].
x2sys_list [INFORMATION]: Crossovers from AS07 minus AS07 [74].
x2sys_list [INFORMATION]: Crossovers from AS07 minus AS08 [142].
x2sys_list [INFORMATION]: Crossovers from AS08 minus AS08 [265].
x2sys_list [INFORMATION]: Crossovers from AS08 minus AS09 [108].
x2sys_list [INFORMATION]: Crossovers from AS09 minus AS09 [173].
x2sys_list [INFORMATION]: Crossovers from IB-2010 minus IB-2010 [1926].
x2sys_list [INFORMATION]: Crossovers from IB-2010 minus IB-2011 [6698].
x2sys_list [INFORMATION]: Crossovers from IB-2010 minus IB-2012 [5774].
x2sys_list [INFORMATION]: Crossovers from IB-2011 minus IB-2011 [2770].
x2sys_list [INFORMATION]: Crossovers from IB-2011 minus IB-2012 [7614].
x2sys_list [INFORMATION]: Crossovers from IB-2012 minus IB-2012 [2999].
x2sys_list [INFORMATION]: Output 75 pairs and a total of 35366 crossover records.
x2sys_report [INFORMATION]: Read crossover database AIRBORNE/AIRBORNE.coe.txt...
x2sys_report [INFORMATION]: Found 57 pairs and a total of 24036 crossover records.
x2sys_report [INFORMATION]: Writing Data Table to Standard Output stream
x2sys_solve [INFORMATION]: Reading Data Table from file AIRBORNE/grav.coe.txt
x2sys_solve [INFORMATION]: Found 35366 COE records
x2sys_solve [INFORMATION]: Determine number of independent track clusters
x2sys_solve [INFORMATION]: 42 tracks form a single connected cluster
x2sys_solve [INFORMATION]: Number of unknowns is 42 and number of constraints is 1
x2sys_solve [INFORMATION]: Matrix equation N * a = b: (N = 43 x 43)
x2sys_solve [INFORMATION]: Before correction, mean and st.dev.: -0.206148 18.0532
x2sys_solve [INFORMATION]: After correction, mean and st.dev. : 0.258629 19.0559
x2sys_solve [INFORMATION]: Writing Data Table to Standard Output stream
gmt [INFORMATION]: GMT_Create_Options: Must expand list file =AIRBORNE/AIRBORNE.lis
gmt [INFORMATION]: GMT_Create_Options: Must expand list file =AIRBORNE/AIRBORNE.lis
x2sys_datalist [INFORMATION]: Your distance unit (e) implies geographic data; -fg has been set.
x2sys_datalist [ERROR]: X2SYS Correction table (AIRBORNE/AIRBORNE.TIME_corrections.txt) requires a column (time) not present in COE database or auxiliary columns
END

No data are put out by x2sys_datalist.

The corrections file produced by x2sys_solve using -Et is attached
[AIRBORNE.TIME_corrections.txt](https://github.com/GenericMappingTools/gmt/files/3453279/AIRBORNE.TIME_corrections.txt)

I am using 6.1.0_cd4cdc4_2019.07.28 on a MacBook Air with Mojave (10.14.6) installed.

The file grav_report.txt, output from x2sys_report, is attached here.
[grav_report.txt](https://github.com/GenericMappingTools/gmt/files/3453291/grav_report.txt)

The file grav.coe.txt, extracted from the entire crossover file by x2sys_list, is attached here;
[grav.coe.txt](https://github.com/GenericMappingTools/gmt/files/3453301/grav.coe.txt)

I can provide other information as deemed necessary, but hesitate to attach the entire database and associated files.