Every player can save up to 10 reserve units. Each player can add their reserve units onto the board.
The exploit involves the following:
- If you have all 10 reserve slots filled up
- And, you add units to the board, where you cannot place anymore units for your level
- If you go into a round of the carousel, and get a unit, then, when you go back into the game, that unit will allow you to
exceed the unit limit for your level; if you continue doing this for every round on the carousel, you could end up with 3+
units beyond the level limit.
It is now possible to upgrade units and buy units from the shop while this exploit is active. I will not detail how, since the game is live with this exploit - however, it needs to be fixed ASAP by Riot.
This is a pretty big exploit if its not fixed soon.