Multiple copies of a field is returned when using api

When using `/sheets/<sheet>`, multiple copies of some fields get returned.  For instance, in our production instance, 'City' gets return 8 times for LFC100Change2020.

No idea why this is, or what might have caused it.  Try and figure out the reason, rather than just doing a "unique" on the list.  Something is getting inserted into the database multiple times, or queried incorrectly.