Not sure when this started happening and if it did so in an update where I missed some functionality change but... Suddenly update requests for users were no longer working.
After doing a lot of testing. I'm able to update the username (name), email (mail), password (pass), first name (field_firstname), and last name (field_lastname). However I'm not able to update any of my custom fields. What is most confusing is I thought the first name and last name fields were custom fields, so I'm baffled as to why am I able to update them but not the others.
The weird part is services returns 200 OK on the calls, and returns a user object containing the values I've sent. However when I go and look at that user, those fields are NOT changed.
I've tried as user 1 to test permissions, I've double checked field names and index requests to ensure spelling/structure is correct - cannot figure out why the custom fields aren't updating.