I think this is why nobody made a Quark Staking Coin, the nasty side effect of staking. Because of it's complexity, it causes Ramhog to take place.
No, your client looks like it has a memory leak. Check to make sure you're calling delete for staking-relevant dynamic allocations.
Also, SeedBit's wallet works for staking without annihilating RAM, so it's probably not Quark's fault.