I would think anything with a JIT that is toggling the page protection for machine code many times a second, based on a very quick reading of the bug report talking about VirtualProtect calls and the processing of ETW events for them by defender.
I don't think anything is toggling them back and forth, it's just that a lot of chunks of executable code are being produced. But I could be wrong; maybe if you have space left for more code on a page, you'll toggle it off and append some new code, then toggle it on again.
My guess is that this would mostly come from inline caches (ICs), since they're typically small and a lot of them are generated.
