Hi Bob,
I'm starting with a blank IPTC field. I hit load and embed the XMP file sent by AP and all the information shows up fine. Then I type a caption in the non AP custom fields and save the snapshot. When it's time to ingest, I double check to make sure everything is there and it is, but after ingestion, the box containing the info I embedded from the XMP is empty. This only happens when I ingest RAW. Yes I can reapply it after ingesting, that's what I usually do, if I remember, but it's not a part of the normal workflow and it adds time on and ingesting with captions is the number one reason I use PM.
I"m using a Nikon D3, Mac 10.5.8, PM 4.6.8.
You said you put a single sentence from a person in the field, can you try creating an XMP, save it to a desktop and load it into the AP custom area? I'm not using the AP Custom button, I'm hitting load and finding an XMP file AP sent to me that I have saved on the desktop and loading it into the custom area.
Thanks for your help.