Discover and transform don't show the same format on the same date field

[Liangliang_Qiu]

When i discover the index pattern=shopee_smart_sorting_my_db__address_match_result_tab*
in Discover, it show the right format of "ctime" field

While when i use transform, it looks totally wrong,

What happened?

add one more point:
when i use transform for index pattern, it shows the column in chart, but no value. Pretty strange!

[walterra (Walter Rafelsberger)]

Can you share the exact version you're using? We can then try to reproduce.

[Liangliang_Qiu]

Kibana's version is v 7.9.2.

the type of ctime field is:
"ctime": {
"type": "date",
"format": "epoch_second"
}

[walterra (Walter Rafelsberger)]

I was able to reproduce your issue in 7.9.2, the date field formatting for epoch_second is wrong in the Transforms UI. It looks like this was fixed in 7.10+ so upgrading should solve the problem for you.

I used these commands in Dev Console to verify:

PUT /test
{ "mappings": {"properties": {"post_date": {
    "type":"date",
    "format":"basic_date_time||epoch_second",
    "store":true
} } } } 

PUT /test/_doc/2
{
  "user" : "test1",
    "post_date" : "20150101T121030.000+01:00"
}

PUT /test/_doc/1
{
  "user" : "test2",
    "post_date" : 1521389162
}

GET test/_search 

Transforms UI 7.9.2:

Transforms UI 7.10.2:

Let us know if you get still empty cells in other columns after the upgrade. There were some related fixes in regards to nested field across some releases.