Whether or not your mace collision boxes get out of alignment depends on the orientation of the Snapper the Z-tek is mounted on. If the Snapper is vertical, such that the Z-tek sags once there is a lot of weight on it, then the mace collision gets messed up. But if the Snapper is horizontal, or if you're not using a Snapper, then the maces are just fine.
As for the explosions at the start of the match, it is as Trovaner said. Because the bot's moving parts can't adjust to the arena while the game is paused.
