I've not had that problem at all, but I always leave it standing up. I can't really find one thing to complain about with this thing. The airflow control is just brilliant. A local shop just got a batch in and I'm gonna pick up another when my Neme arrives next week.
BTW, do you know how to break it down for cleaning? Normally I would just figure it out but I'm afraid of screwing this one up.
I opened up my air intake just a fraction of a fraction more, and have not had any liquid build ups since then. Not sure about disassembly. Haven't dared to try it myself
Couldn't be more happy with the Kraken. It occured to me that the small size fill hole might prevent it from leaking if left on its side. Sure does. At least with my 50/50 liquids.