esoteric packrat::status() warning message after 'up to date' message about dependencies

Don't really know what this means

> packrat::status()
Up to date.
Warning message:
In value[[3L]](cond) :
  Failed to parse /var/folders/w7/cmnsdwfs30d6qc0ww6cypbb00000gn/T//RtmpypSGab/fileaa3464d1788 ; dependencies in this file will not be discovered.

project is version controlled with git in a local folder (not in dropbox or some other thing that can cause sync conflicts)

Session info ---------------------------------------------------------------------------------------------------
 setting  value                       
 version  R version 3.1.2 (2014-10-31)
 system   x86_64, darwin14.0.0        
 ui       RStudio (0.99.292)          
 language (EN)                        
 collate  en_US.UTF-8                 
 tz       America/New_York            

Packages -------------------------------------------------------------------------------------------------------
 package    * version    date       source                            
 assertthat * 0.1        2013-12-06 CRAN (R 3.1.2)                    
 chron      * 2.3-45     2014-02-11 CRAN (R 3.1.2)                    
 colorspace * 1.2-6      2015-03-11 CRAN (R 3.1.2)                    
 data.table * 1.9.4      2014-10-02 CRAN (R 3.1.2)                    
 DBI        * 0.3.1      2014-09-24 CRAN (R 3.1.2)                    
 devtools   * 1.7.0      2015-01-17 CRAN (R 3.1.2)                    
 digest     * 0.6.8      2014-12-31 CRAN (R 3.1.2)                    
 dplyr        0.4.1      2015-01-14 CRAN (R 3.1.2)                    
 evaluate   * 0.5.5      2014-04-29 CRAN (R 3.1.2)                    
 formatR    * 1.0        2014-08-25 CRAN (R 3.1.2)                    
 ggplot2      1.0.1      2015-03-17 CRAN (R 3.1.2)                    
 gtable     * 0.1.2      2012-12-05 CRAN (R 3.1.2)                    
 knitr        1.9        2015-01-20 CRAN (R 3.1.2)                    
 labeling   * 0.3        2014-08-23 CRAN (R 3.1.2)                    
 lazyeval   * 0.1.10     2015-01-02 CRAN (R 3.1.2)                    
 magrittr   * 1.5        2014-11-22 CRAN (R 3.1.2)                    
 MASS       * 7.3-39     2015-02-24 CRAN (R 3.1.2)                    
 mlxR         2.1.1      2015-03-17 Github (MarcLavielle/mlxR@aa4599b)
 munsell    * 0.4.2      2013-07-11 CRAN (R 3.1.2)                    
 packrat    * 0.4.3      2015-01-29 CRAN (R 3.1.2)                    
 PKPDmisc     0.3.0.2    2015-03-20 Github (dpastoor/PKPDmisc@ac08c3a)
 plyr       * 1.8.1      2014-02-26 CRAN (R 3.1.2)                    
 proto      * 0.3-10     2012-12-22 CRAN (R 3.1.2)                    
 Rcpp         0.11.5     2015-03-06 CRAN (R 3.1.2)                    
 reshape2   * 1.4.1      2014-12-06 CRAN (R 3.1.2)                    
 rstudioapi * 0.2        2014-12-31 CRAN (R 3.1.2)                    
 scales     * 0.2.4      2014-04-22 CRAN (R 3.1.2)                    
 stringr    * 0.6.2      2012-12-06 CRAN (R 3.1.2)                    
 testthat     0.9.1      2014-10-01 CRAN (R 3.1.2)                    
 tidyr        0.2.0.9000 2015-03-18 Github (hadley/tidyr@3de52c4)     
 XML        * 3.98-1.1   2013-06-20 CRAN (R 3.1.2) 

Start by reproducing packrat::status() in the reported R 3.1.2 and RStudio environment, then trace the dependency parsing that emits the temporary-file warning. Review the status output and package versions in the report; done means the warning's cause is understood and the behavior is covered by an appropriate regression check.