Do you mean the user field issue is on the new form? Not to bail on a solution but if the issue is with new forms your best bet is to submit a ticket to QB or bash it enough times until you can see how it might be happening while bugs with the new forms are worked out. If you have the field required on the form but it's not requiring it before your user saves then something about the form configuration isn't firing for QB to review.
If you need the extra validation on the user field - you could try using a custom data rule to check that the user field is populated as a secondary precaution. Doesn't fix the bug on the form but at least some piece of mind in the interim.
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Chayce Duncan
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