Get latest value and calculate yesterday same timestamp value

I want to check "the value of my current hour" and "the value of previous hour" (within 7 days) every hour and compare whether the difference between the two exceeds the threshold I set.
The "current query" is the current value, and the "past query" is the value of the last search.
For example, I compare the value of 2 p.m. between 8/5 to 8/1, I have a specific field "timestamp" that will record my timestamp, which is a string type.
(ex.
2021-08-05T06:00:14Z 3.123195641829014 INFO
2021-08-04T06:00:22Z 3.648548028550934 INFO
2021-08-02T06:00:14Z 2.9963953099600076 INFO
2021-08-01T06:00:12Z 2.7667300671179333 INFO
)

And calculating the value of both 8/5 and 8/4, 3.1-3.6= -0.5
But when I checked my outputDB, it seems that I missed some steps, so I got the same value which I have filtered through the "offset".

The following are my tick scripts:

```
var groupBy = *

var name = 'ＣＰＵ batch relative monitor'

var idVar = name

var message = '{{ if eq .Level "OK" }}recover：{{ else }}alert：{{ end }}{{ .ID }}

{{ if eq .Level "OK" }}recover time：{{ else }}alert time：{{ end }}{{ .Time.Local }}

host：{{ index .Tags "host" }}

level：{{ .Level}}

{{ if eq .Level "OK" }}recover value：{{ else }}alert value：{{ end }}{{ index .Fields "value" | printf "%0.0f"}}%
'

var idTag = 'alertID'

var levelTag = 'level'

var messageField = 'message'

var durationField = 'duration'

var outputDB = 'chronograf'

var outputRP = 'autogen'

var outputMeasurement = 'alerts'

var triggerType = 'relative'

var shift = 30m

var crit = 100

var period = 2m

var chatId = 'xxx'

var cron = '0 * * * *'

var current = batch
|query('''
select value from "normal"."autogen"."cpu" where ( cpu =~ /cpu-total/ ) AND ( timestamp =~ /T14:00/ ) order by desc
''')
.period(10m)
.cron(cron)
.groupBy(groupBy)

var past = batch
|query('''
select value from "normal"."autogen"."cpu" where ( cpu =~ /cpu-total/ ) AND ( level =~ /INFO/ )AND ( timestamp =~ /T14:00/ ) order by desc
''')
.offset(10m)
.period(7d)
.cron(cron)
.groupBy(groupBy)
|shift(10m)

var trigger = current
|join(past)
.as('current', 'past')
.tolerance(2m)
|eval(lambda: float(abs("current.value" - "past.value")))
.keep()
.as('value')
|alert()
.crit(lambda: "value" < crit)
.message(message)
.id(idVar)
.idTag(idTag)
.levelTag(levelTag)
.messageField(messageField)
.durationField(durationField)
.telegram()
.chatId(chatId)
.parseMode('Markdown')

trigger
|eval(lambda: float("value"))
.as('value')
.keep()
|influxDBOut()
.create()
.database(outputDB)
.retentionPolicy(outputRP)
.measurement(outputMeasurement)
.tag('alertName', name)
.tag('triggerType', triggerType)

trigger
|httpOut('output')
```

this is my influxdb output

```
> select value,level,timestamp from cpu where (host =~ /etc/) and (timestamp =~ /T14:00/) order by desc limit 4
name: cpu
time value level timestamp
---- ----- ----- ---------
2021-08-05T06:00:14Z 3.123195641829014 INFO 2021-08-05T14:00:14+08:00

2021-08-04T06:00:22Z 3.648548028550934 INFO 2021-08-04T14:00:22+08:00

2021-08-02T06:00:14Z 2.9963953099600076 INFO 2021-08-02T14:00:14+08:00

2021-08-01T06:00:12Z 2.7667300671179333 INFO 2021-08-01T14:00:12+08:00
```

and this is my kapacitor task status

```
DOT:
digraph test-job {
graph [throughput="0.00 batches/s"];

query2 [avg_exec_time_ns="0s" batches_queried="1" errors="0" points_queried="1" working_cardinality="0" ];
query2 -> shift3 [processed="1"];

shift3 [avg_exec_time_ns="2.771µs" errors="0" working_cardinality="0" ];
shift3 -> join5 [processed="1"];

query1 [avg_exec_time_ns="13.396881ms" batches_queried="1" errors="0" points_queried="1" working_cardinality="0" ];
query1 -> join5 [processed="1"];

join5 [avg_exec_time_ns="55.59µs" errors="0" working_cardinality="1" ];
join5 -> eval6 [processed="1"];

eval6 [avg_exec_time_ns="0s" errors="0" working_cardinality="1" ];
eval6 -> alert7 [processed="1"];

alert7 [alerts_inhibited="0" alerts_triggered="0" avg_exec_time_ns="2.39µs" crits_triggered="0" errors="0" infos_triggered="0" oks_triggered="0" warns_triggered="0" working_cardinality="1" ];
alert7 -> http_out10 [processed="0"];
alert7 -> eval8 [processed="0"];

http_out10 [avg_exec_time_ns="0s" errors="0" working_cardinality="0" ];

eval8 [avg_exec_time_ns="0s" errors="0" working_cardinality="0" ];
eval8 -> influxdb_out9 [processed="0"];

influxdb_out9 [avg_exec_time_ns="0s" errors="0" points_written="0" working_cardinality="0" write_errors="0" ];
}
```

When I am trying to run the tick scripts, that doesn't work, even this crit condition definitely should triggered.
I couldn't find any references. Any suggestions are appreciated. Thanks.
My kapacitor version is 1.5.7 and influxdb version is 1.8.3

Review the supplied TICKscript, query definitions, task DOT output, and Kapacitor 1.5.7/InfluxDB 1.8.3 versions first. Reproduce the task behavior and determine why the alert condition and output nodes process no points; the issue is done only when the cause and an actionable fix or documented limitation are established.

Written by the indexing model from the issue text.