Text shown in screenshot below is a non-standard font (some monospace thing) and is embedded in the page. Would either of these factors prevent AutoMark from correctly identifying contents?
It looks like SHX font (as opposed to a truetype font) which is probably represented as linework and not text in pdf files. If you run OCR then it should become recognizable as text.
Result is literally [Region 1]. Screen recording attached.
FWIW: other tools like AI chatbots can't seem to recognize these fields either. It's almost as if there's nothing in the region. Probably an issue with the software that generates the PDFs in question.
Thanks for the recording. So you see "[Region 1]" as the Page Label in Thumbnails Panel instead of "6-B3".
I'm going to delete my response and see if anyone else has any ideas.