I’m not sure if you could choose a date format for Date Custom Fields in the past. I never really checked. Since you are claiming this is the issue, I will put it into the bugs category to get some extra attention. The topic is similar to this. Custom fields date format not working correctly - Manager Forum
I have also noticed sorting problems somewhere else in the program (Bank and Cash Account) after investigating your issue.
I believe the first columns should be used for sorting in the tabs. Or at least, the user should be able to select the preferred Column for sorting.
The mix-up after pasting from “copy to clipboard” and the sorting issues are likely linked to the Edit column update. It will be checked also. I have also experienced one where a long list of payments had at least two items appearing in the wrong column.
Below is an example of a description text pushing the amount from its cell.
Version: 23.3.12.689