Photos auto deleting from text messages

I'm having an issue where photos will randomly disappear from a text conversation. Nothing is left in their place, no text bubble, no download option, just gone completely. Any words sent with it will still be there. I can't find them in my photos or anywhere else. So far, I can only confirm it's with 1 specific person, but many photos and videos remain in our chat. Only some disappear. I don't use iCloud. I have iMessage enabled. I have send as SMS when iMessage is unavailable enabled. I have keep messages forever enabled. The other person doesn't know of any settings they have selected that would cause this. The other person has an iPhone 14. I have a iPhone 12 Pro running 16.5.1. This has been happening for about 3 months. My phone has recently become almost full, but it wasn't as full when I first noticed this. Right now I have 4 gigs available out of 128.