Question Flashes appearing with my projector

[axlrose]

Watching the NFL playoffs and getting some occasional flashes on parts of my screen. Wondering how to diagnose if this is a bulb, or ISP, or the broadcast etc. I've never seen it before.

Thanks.

 

[axlrose]

I might be getting an occasional drop for a second too. Feels like a problem with my HDMI cable, but I don't think anything has changed in it from the last few years.