Stutter - please help as it is not my hardware

Description:
I have a reproducible stutter issue that only occurs on my Pandaren Monk in Windwalker spec. This is not a hardware or client configuration issue — I’ve tested extensively and isolated the problem

What happens:

Every ~5 seconds there is a clear stutter (both visual and FPS hitch).

Switching to Brewmaster on the same character removes the stutter.

Other characters do not have this issue.

Platforms tested (fresh installs, no addons, default CVars):

  1. Steam Deck (Linux)

  2. Mac M1 (macOS)

  3. Windows 11 desktop – AMD 7800X3D, Radeon 9070XT, 32GB RAM @ 6000MHz

Troubleshooting done:

Fresh installs on all platforms

No addons, cache cleared, CVars reset

Deleted WTF/Interface/Cache folders

Tested on different networks

Reset talents/spec multiple times

Happens regardless of graphics settings or resolution

Key finding:
If I unplug the internet cable while in-game, the stutter stops instantly. Plugging it back in causes it to return. This strongly suggests the cause is related to server communication for this specific spec/character rather than local hardware or settings.

Steps to reproduce:

  1. Log into my Pandaren Monk.

  2. Set spec to Windwalker.

  3. Observe consistent stutter every ~5 seconds.

  4. Switch to Brewmaster – stutter disappears.

  5. Unplug internet while in-game – stutter disappears instantly.

I raised a ticket three weeks ago and still having an issue.

Please can someone help or tell me what I can do here?