Udemy Video Going Black on Safari

I have MacBook Air M1. Running on Mac OS Monterey 12.2. Whenever I try to play courses on Udemy on Safari with external monitor connected, it is just black screen, audio goes fine. Although videos play properly without any problem on Chrome. (with external monitor connected). Without monitor, videos play well on Safari.

Problem is only when external display is connected and only with Safari. Does anyone know the solution?

I think many folks are noticing this, it is still not resolved.