Everything worked on version 2.7.1 and subsequent master versions until some recent commit before the new release. Before that, there were a lot of commits on WoW 3.3.5.a. I thought someone had discovered this and would run an API trace, as I don't have time for that.
I simply reported the issue. If you don't need it, you can ignore it and will use the previous version of dxvk.

Recording an apitrace following the instructions should take you no more than 10 minutes. Figuring out how to setup old WoW on some private server and then learning how to even trigger this issue in the game could take someone else who's not familiar with the game hours.

https://github.com/doitsujin/dxvk/actions/runs/27920966270 this buid dont have issue, next buld have label problem.

https://github.com/doitsujin/dxvk/actions/runs/28244051206
latest master have same issue.

I dropped the files for recording the trace into the game folder and switched the markers above the player.
Trace: https://drive.google.com/file/d/1rc7_lMjd0qF41IKhkrWHfT5yrBJ46t-y/view?usp=sharing
How records trace with https://github.com/doitsujin/dxvk/actions/runs/28244051206 d3d9.dll or dll after https://github.com/doitsujin/dxvk/actions/runs/27920966270?

Okay new info.
try latest master dll again and, if I load game in windowed mode - label blinking/don't show. If I load game in full screen mode - label show normally.
And when i switch fullscreeen to windowed in reallife - label work normally too.
And now after new start game exe in windows mode - label work normally -_-. Switch to fullscreen helps
wow_d3d9.log

Well, found new info.
latest master:
Artifacts (Package) - label on the head works Normal
Test Builds on Windows - label on the head Blink/Hide

https://github.com/doitsujin/dxvk/actions/runs/28539040568 master "Builds on Windows" work with label.