The game fails to register shots and hits made by custom weapons (invisible gun with attached decoration to it) in multiplayer.
It works like this: player "A" kills player "B" on player's "A" screen, however on player's "B" screen player "A" didn't make enough shots to kill player "B". This leads to a situation where player observes how his enemy dies and then instantly ressurects.
I know this happens to regular guns as well. But with custom weapons it is ~3x times more frequent. I think this should be fixed because custom weapons became an important part of todays map development and it would be really sad if map makers wouldn't want to use them because of the mentioned issue.
I have published a small test map with a custom weapon in case if you want to check this issue yourself. Link.