Confirming here. This happens quite reliably after crossing the portal room.
Here a VOD with evidence.
When I log in into the portal room the FPS runs fine.
When I teleport from Valdrakken to portal room, the FPS drop starts. It does not on every zone, but notably when there are many NPCs on screen.
Notice that when I left Valdrakken there was some kind of environmental effect on. The portal room’s skybox took a while to change from the custom effect to the default. Also the this issue only started happening yesterday, despite the wow client not getting updates recently.
At Waycrest entrance, FPS drops to 40.
Even after disabling all addons, it remains at 40. /console gxrestart seemed not to work too.
After restarting the game, Waycrest FPS goes back to cap (144).
Im running an MSI RTX 3060Ti + Intel 12600KF at Windows 11 22631.2428