The Linux VR Adventures Discord has been complaining about this for few weeks now, so we think this should be fairly easily reproducible.
When a video player loads a video through Proton, the game hangs fully for a short bit. Some users report 3-5 seconds. This makes for a really bad experience, especially when video playback fails and it'll continuously retry.
LVRA thinks the issue started popping up around April 23rd, the VRChat Proton issue at https://github.com/ValveSoftware/Proton/issues/1199#issuecomment-2078623279 thinks it specifically happened from OB 2024.2.1-1446-4e35ef12c2-Release
Reproduction steps:
  1. Start VRChat on Linux through Proton
  2. Load a video in the video player
  3. The game will completely hang with 'Attempting to resolve URL' as last log output until the yt-dlp process is logged as started
Although technically another issue, opening profile links makes a similar hang appear which might be a clue towards URL handling being the core issue.