Please revert the multiplier reset.
You "fixed" one problem (people waiting until the 2nd round to join when banner balance kicks in) and created more. Now people either have to suicide rush the enemy (which hurts their team) or just hide somewhere if they go AFK, both are obvious cases of leeching. Before they could do the respectful thing and go spectator and come back and still have their multiplier (assuming their team won the round they went spec).
I honestly don't think that many people waited for the banner balance on 2nd round, so your fix only fixed a few game exploiters, but your multiplier reset affects 100% of the players.
I know that everyone in Hospitallers when we're on teamspeak always join the first round and we fight it out to keep our multiplier. It's a lot of fun actually (fuck banner balance in general, but that's another topic).