An example of this is a strange bug within Boss Spawn plugin in alliedmodders.
When you set it so that opening the saferoom door will spawn tanks, tanks will not spawn until all players who were on a previous map finish connecting in the current match (this does not affect players currently joining the actual game)
I think there are other plugins that vslib would conflict with.

Examples:
https://forums.alliedmods.net/showthread.php?t=323402