Sounds like the oil pump seal has dropped out which means it just pumps the 2t into the gearbox, when the gearbox fills up it just pumps it out of the gearbox breather. Very common problem and easy to fix, remove the pump and bond the seal back into place.

Disconnecting the oil feed pipes wont stop it happening as the pump will still be pumping oil.

With HRC's current dominance in moto gp I'm sure they will have plenty of spare time to work on a fix for your mc18