However, highlander never seems to devolve into a stalemate where neither team is attacking or defending.
Worth noting that the reason highlander never ends up the stalemate state that 6's ended up in is teams are always either attacking or defending in highlander, they aren't doing both. 6's doesn't have stalemates on koth, because after the mid fight there is one team that must push, and one team that must defends. There were tons of stalemates in HL when we were running 5cp maps. Stalemates are a map/gamemode issue.