A NEW SUSPICOUS ADDON THAT CAN CAUSE MANY PLAYER UNINSTALL-REINSTALL GMOD!
So theres the bait...
many people install the prone mod etc.
after installing the main addon that makes animations etc.
makes the player who installed the addon go T pose after death
the addon makes the game "update" like a update to the game
instead of being in the "addon download menu" when addon is being downloaded
it displays it in the bottom of your screen. but this one isnt like other ones
instead it updates your game, i turned off every addon same issue
so i had to re-install the game and bingo. it worked it might be a creator issue
but im just gonna leave it here for further inspect / testing
http://gtm.steamproxy.vip/workshop/filedetails/?id=757604550

I remember this being posted on FacePunch so I doubt it would have a backdoor or anything and looking through the code it has nothing of the sort.

Found another
https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=918339073

Another one - http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=1076978429