Games suddenly stuttering while in a video call after the "reduced video call cpu usage by 50%" update

I've been playing many games on my desktop while on a DM video call with no problems for years now. League at 100fps and other more demanding games ran smoothly. But in the past few weeks I've been experiencing bad stuttering and FPS drops.

Even if I cap League to 60fps (which a potato should be able to run), I get stuttering every 15s or so (sometimes more, sometimes less). After each stutter, the in-game FPS counter displays half of the cap before going back to normal (e.g. if I cap it at 100, it shows 50 for a few seconds, if capped at 60 it shows 30). Everything runs smoothly again if I disable video for the person I'm calling.

This all started around the time I saw the "reduced CPU usage during video calls by 50%" changelog entry. I was excited at the prospect of getting better framerates with this update...needless to say I'm disappointed that it seems to have the opposite effect for me.

Looking at hardware monitors, it seems that video calling is causing my GPU to ramp up intermittently, though I'm not sure if this was also the case when everything was running smoothly. Disabling hardware acceleration seems to increase CPU usage dramatically and makes performance even worse.

Anyone else experiencing this? Very frustrating that my performance has seemingly been arbitrarily nerfed by this update...

Stable 89477 (0e3193f)
Host 1.0.9002
Windows 10 64-Bit (10.0.19041)