Starts normal then bars disappear (sdl_glsl)

[rdnamil]

Describe the bug

When setting the output mode to 'sdl_glsl', it will start normally but then after a couple of seconds the bars will dissapear.

To Reproduce

Steps to reproduce the behavior:

1. Set output mode to 'sdl_glsl'
2. run
3. wait a couple of seconds
4. See error

Expected behavior

Bars not disapearring.

Screenshots

2025-12-04_12-49-15.mp4

Desktop (please complete the following information):

• OS: EndeavourOS
• Version 6.17.9-arch1-1

Terminal emulator

• ghostty v1.2.3-2
• alacritty v0.16.1-1

Additional context
I've also tried changing enabling synchronized_sync, continuous_rendering, and disable_blanking. Changing these settings don't seem to make a difference.
Everything works as expected when output is 'ncurses' or 'sdl'.

[karlstav]

strange, can't seem to reproduce. Are you on latest version? Have you tried any of the other shaders?

[rdnamil]

Yup, on the latest. I've tried using the -git package from the Aur and building from source. Happens with both and with different shaders.

[karlstav]

Does it always disappear after exactly the same amount of time?

Also what gpu do you have and what drivers?