... and after an update this morning the issue seems to be resolved, sorry for bothering you!

these are exactly the steps I usually take -

1. I upload 2 - 20 files that have the same subject, so they should have the same file name with added numbers
2. I enter the appropriate title in the title field, choose a caption and description, categories and whatever else is needed
3. I click on "Copy information to all uploads following..." and check if all relevant boxes are checked, including the "Copy title (with automatic numbering)" box and then click on copy

I still experience this issue on my Windows laptop running on Windows 10 pro.

working again