Custom name picker field empty after submission on Portal

[Bill Mc]

On a portal, I have a request type that has a 'manager' field.

• field is name picker, required, and added to relevant screens for the request type
• When creating, manager works as expected and user can type / select a name
• When they click submit, the details view shows Manager as blank
• Issue view shows manager as blank
• history/work log show NO changes after submission

Probably a simple fix, but it's driving me mad.  I've removed the field, toggled it from required to optional and back, changed the order of the field, nothing is giving me any positive result.  
Any thoughts on this one are greatly appreciated.

[Bill Mc · Accepted solution]

Post functions get you every time.  In this case, there was a post function on create that was setting Manager to a null value. Zero Idea why anyone would have put that there, but they did.  Carry on.