I just replaced two images uploaded by a different user and I noticed that next to pending there is an exclamation mark in a circle.

https://e621.net/post_replacements?search%5Bcreator_name%5D=Kemonophonic

Anyone know what this means? I've never seen this happen before.

kemonophonic said:
I just replaced two images uploaded by a different user and I noticed that next to pending there is an exclamation mark in a circle.
...
Anyone know what this means? I've never seen this happen before.

Hover your mouse over the symbol and see a couple of apparently relevant tags on the pictures — better_version_at_source (for the one with X-ray view) and conditional_dnp.