Survivor in the dying state was able to prevent themselves from being picked up.

AquaSurferGames

Note: this occurred on the steam version of dbd, on the map called temple of purgitation

I managed to down multiple survivors in the same area, and started hooking them. However, one Dwight was able to prevent me from being able to pick him up, by crawling under the person on hook right next to him. If he positioned himself correctly, the prompt to pickup a survivor would not show up at all and I was forced to give up on trying to hook that Dwight.

How to recreate this yourself:

1. down 2 survivors near the same hook
2. Hook one of the survivors
3. If the other survivor attempts to crawl under the person on hook, you won't be able to pick them up.

This has so far only occurred to me once, but it's possible that this is just an unknown exploit that could be abused (for example, being able to use unbreakable under the person on hook and unhooking them immediately).