Are there issues currently with QoS on the latest firmware?

I reckon you need to prioritize the Call Of Duty traffic specifically. This will involve disabling DumaOS Classified games under Traffic Prio, adding your device manually and choosing the Call Of Duty profile.

Also, if the streaming and gameplay are coming from the same device, anti-bufferbloat won't help much, so probably turn it off for now (select Never)

Basically you want to give the stream enough bandwidth to breathe, but still make sure that Call Of Duty is prioritized. It might be good, depending on your connection speed, to set the quality of the stream manually. For example, if your connection could only occasionally handle 1080p, it would be better to set it to 720p.