Changes made in the Jira Cloud Desktop browser interface are not reflected automatically in the mobile app (Android) when you open a Work Item. In order to be sure you are viewing the most recent data in a Work Item in the mobile app, you have to pull down after opening the Work Item to force a data refresh.
I would like to create an Automation that fetches new data in the mobile app each time you open a Work Item, but I can't find any Trigger that seems to address that situation.