When using the negate node "-pvpmanager.nocombat" ops players still get pvp disabled by default and always have to type /pvp after they login.

Well, considering how long it took me to answer, you probably don't care anymore but the permission you have to negate is pvpmanager.nopvp. Sorry for the delay.

Actually I'm still using PvpManager and still got the issue. Thank you for answering.