This is delayed follow up to this problem that hopefully will help others.
The cause appeared to be the use of ‘autocomplete’ appearance parameter in the ‘select_one’ or ‘select_one_from_file’ in certain cases. The certain cases which caused the problem were hard to determine exactly and others had slightly different experience than us but the following post was very helpful:
https://community.kobotoolbox.org/t/enketo-typeerror-cannot-read-properties-of-null-reading-dataset/27328
In our case it seemed like it was cause by using with ‘select_one’ referencing the same choices list a 2nd time after the first reference used ‘autocomplete’, or it was caused by using ‘select_one’ in a nested repeat. In our testing, it didn’t seem like ‘autocomplete’ could be used after the nested repeat for any list so sadly, we modified our form to remove all the ‘autocompletes’ after the nested repeat.
