Hi there!
Being that the issue is caused by memory leakage from faulty code, there is no reason to automatically suspect Anti-Virus but it is a good starting point, from there I would investigate non essential programs that run in the back ground. Such as Rainmeter or
Steam Client Bootstrapper, kill these processes one by one and then once the memory drops back down to a reasonable level you can reopen the suspect program/process to definitively say whether or not it is that program causing the issue.
Pros: You may find the program causing the issue, and can inform the company that made the program about it
Cons: If you have had your computer for a long time, it might take a while to enumerate your programs and then cycle through turning them off and on again, also if it turns out that it is none of your already installed programs, it might be your OS which would
be harder to fix.