That's a good question. Could be a memory bug in the particular apps you use. Hard to say without knowing specifics. I doubt its a fault in your hardware, but remember that there is both the OS that is managing, and then the app itself which can have issues.
I'm sorry I can't help more, but have you tried writing to the developer of the particular app you're having issues with?
Yeah I've sent in reports before to them about it, but haven't seen any updates. Either way, more ram would never hurt the situation!