The update time of command is different from that of UI

when I use the restapi command to get the  modified_at like follow, sometimes it is diffrent form the updated at UI.can you tell me the rule.Because I want to use the paramter to do something related the business.I try to change the filename, the command's modified_at is changed but the UI is not changed. And I also find There is time zone between them。For example the "modified_at": "2021-12-12T23:01:43-08:00".But the UI is "Dec13,2021"

"modified_at": "2021-01-01T10:53:43-08:00",