Hi Marianne.
I have been to Jo-burg twice, wish I lived there.
I think the issue is probably how you are updating the field. If you set the value from outside of the repeating table it will set the same value for all records.
Best thing is to always create a data dump view.
Drag all fields onto it. Both Query and Data.
Then add some buttons to switch back and forth.
Use it to verify your data in the form periodically as you work through your main view and especially before submit to see what is happening behind the scenes with your data.
You may need to use filters or the current() function to make sure you are only updating the correct record rather than all.
Let me know what you find.