Unable to delete duplicate photos on my iPhone 12 Messages

I was reviewing photos with one of my contacts and noticed there were dozens of duplicates of one photo. I was able to delete them but after reopening messages, they reappeared. There are multiples of photos duplicated on this chat. Not all photos are duplicated though. It was so bad, that chat used up 3 GB of space. I deleted the chat.

I checked another chat and noticed the same, with 100's of duplicates of a photo. None of the photos that are duplicated are in my photos folder. I have attached a very, very small sample from one chat. I can't find anything online anywhere. I'm not syncing messages or photos to iCloud though i do use a few devices.

[Edited by Moderator]

Original Title: Duplicate photos in Messages - iPhone 12