Could it be related to mandatory Widevine encryption?

On my phone, the mobile site (m.youtube.com) has introduced Widevine a couple of weeks ago (last week of August IIRC). No idea if I’m just unlucky and part of a shitty A/B experiment, but I definitely had to recompile libc (being on Linux) with patches from Chromium and install Widevine so I could watch videos again.

Whenever I replace my patched libc with the unpatched original, then the Widevine plugin crashes everytime I try to play back a video on m.youtube.com. And it used to work before.