Unable to add additional fields

I’m trying to add on additional fields to my form, but each time I save, it reloads without the field I just added. I have 22 fields and I’m trying to add the 23rd field. I didn’t read that there’s a limit to the number of fields. I’ve added fields to other default forms with no issue. I’ve even cloned this revision and tried adding more fields there with no luck.

Any ideas?