I never had this issue for years before only recently faced spectating problem. When I join room to spectate it never launches the game whether mod or non mod match. If I close the room after 5 mins of waiting it will show me in lobby as I am still inside the room unless i close lobby and rejoin.

However only once by mistake when I joined a room in which client prompted me to do download the mod as I didnt had ... it followed the steps to make me download and I was able to spectate ONLY that game.

I already reinstalled voobly and the game but it didnt helped.