I have a very simple flow - it shows contacts filtered by one field. The dynamic choice is displayed using radio buttons (drop down shows the same behaviour). When I choose an option and click on next, a message appears "Please select a choice". If I filter by different fields, sometimes it works as expected, sometimes it doesn't. On different sandboxes filtering by that particular field works, not on others.
This seems to be an issue with the particular field, but I cannot see any difference between fields or sandboxes.
All fields used are definitely visible by me - filter field, id and label field.
Is there anything on the field definition that might cause this issue?
The flow in all its simplicity - I cannot see anything that I might change in order to correct this:
Addendum: the filter above returns 10 results: