Deleted iMessage large attachments reappear on iPhone

I am having issues deleting large attachments from iMessage on my iPhone.

I turned off Messages in iCloud, so my messages should not be syncing or backing up to iCloud anymore. However, when I delete videos and photos from Settings > General > iPhone Storage > Review Large Attachments, they reappear shortly afterward. In many cases they return as duplicates or even multiple copies.

Here is what I have already tried:

• Turned off Messages in iCloud
• Deleted large attachments through iPhone Storage
• Restarted my phone
• Checked iCloud.com to see if messages or attachments were stored there

Despite these steps, the attachments keep coming back and sometimes appear two or more times.

How can I permanently delete old videos and photos from the Large Attachments section of iMessage without them reappearing?