Here is a copy of the "Show details" of the error.
I also found out that if I remove all of our repeats groups and only leave one on the Feature Report template, it works.
If I have two or more repeats groups then it gives me the same error.
We have a total of 4 repeats groups, so this is definitely an issue.
Please let me know what you are able to find out from your ends why the repeats are creating such error.