Netflix shortcut ctrl-alt-shift-d not working on buster, but works on sparky/bullseye (Firefox 80)

EDIT: Solved (scroll down for details)

This one has been puzzling me...

On netflix, while watching a video, if you press ctrl-alt-shift-d it should show you some detailed info about the stream.

This shortcut works on SparkyLinux (based on/using bullseye repos), both on sparky's packaged firefox and on firefox 80 binary downloaded from mozilla.org.

On Debian buster, either on firefox-esr 68 or the Firefox 80 binary from mozilla.org mentioned above it doesn't work (nothing happens).

Running XFCE on both systems. Also tried MATE on buster with same result.

First thought was that that shorcut was bound to something else on buster, but couldn't find anything.

Ctrl-alt-shift-s (which shows a menu to select some streaming options) works on Firefox 80 on both systems.

Any hint/idea on what may be blocking/catching this shortcut on buster and not sending it to netflix? Or how I can debug this?

I thought of trying this on a debian bullseye live cd to see if there's any difference between vanilla bullseye and sparky's version but I couldn't find a live cd ISO for bullseye... There's no isos on the weekly build dir in Debian's cdimages.

EDIT: found the culprit - it was skypeforlinux that was catching the shortcut even if didn't have the windows focus. Quitting skype (make sure it's not running on background) solves the problem.