I just filled in a bunch of NLP specific metadata and went to export my images (making TIFFs). It hangs for a bit and then fails with message:
Unable to Export
An internal error has occurred: Exif.lua:30: attempt to perform arithmetic on local ‘n’ (a nil value)
I receive the message from the export option in the NLP window and the standard export dialog.
I suppose I will try deleting each piece of metadata looking for a trigger. This really seems like a bug.