There is the following problem with Telegram that is shipped as the 'telegram-desktop' package. In a video call, both a video from the other party's camera and a video from the other party's screen ("Screencast" function) appear as black boxes. There are two interesting things:

1. If use Telegram that is shipped as a Flatpak package from Flathub ('org.telegram.desktop'), then the problem persists but can be fixed by installing 'xorg-xwayland' pacman package. Surprisingly, the problem persists in Telegram from pacman, after reboot also.

2. The black boxes presumably have a correct aspect ratio (if the other party shares a vertical video, I'm seeing a vertical black box).

I haven't found any fix for that online. Any ideas on how to fix Telegram from pacman? Thanks!