SUMMARY
Sometimes, when maximizing a Chrome window or dragging it from one monitor to another, the window frame doesn't render properly and the contents of the window are rendered by an offset the height of the frame. This most likely only happens to Chrome windows in PWA mode. This seems to be an issue only with wayland.

Usually, the problem is fixed most of the times by restoring and maximizing the window via keyboard shortcuts at least twice. Sometimes it helps dragging the window back to the previous monitor (via win+mouse), then moving it back to the other monitor.

A similar behavior can be observed with OBS docks when undocking them, tho usually, the contents of those docks do not render properly at all. So this is probably unrelated or has a very different effect.

While Chrome (and OBS docks) render their own window decorations, and it may thus be their fault, maybe there's a race condition in kwin? I couldn't reproduce the rendering problems in X11 with Chrome, but I could reproduce the rendering problems in X11 with OBS. I'm currently on Wayland. This bug report is about Chrome, OBS is just a side note.


STEPS TO REPRODUCE
1. Make a window an PWA app using the Chrome tools menu
2. Drag the window to a different monitor and drag it to the top edge to maximize, or open the PWA app from the Plasma menu and maximize it
3. Observe that (only sometimes) the window will render without border and mouse hover effects and click positions are offset from where you click
4. The window frame is still there, just not rendered: you can click where you expect the frame buttons to close or minimize the window
5. Restore/maximize multiple times to make the window render properly


OBSERVED RESULT
Maximized windows may render without a window frame but click positions inside the window are offset by the size of the frame.


EXPECTED RESULT
The window frame should render properly, and window contents should render to the correct position.


SOFTWARE/OS VERSIONS
Operating System: Gentoo Linux 2.17
KDE Plasma Version: 6.3.2
KDE Frameworks Version: 6.11.0
Qt Version: 6.8.2
Kernel Version: 6.12.18-gentoo (64-bit)
Graphics Platform: Wayland
Processors: 20 × 12th Gen Intel® Core™ i7-12700K
Memory: 31.1 GiB of RAM
Graphics Processor 1: NVIDIA GeForce RTX 3080 Ti
Graphics Processor 2: Intel® UHD Graphics 770
Manufacturer: ASRock
Product Name: Z690 Pro RS

NVIDIA-SMI 570.124.04
Driver Version: 570.124.04
CUDA Version: 12.8


ADDITIONAL INFORMATION
This looks like a race condition. It's unreliable to reproduce, and if it happens, it may happen multiple times in a row with different Chrome windows. I've rarely seen a full Chrome window with tabs render improperly, and I am currently only able to reproduce the problem with PWA apps. This is on Wayland.

I've seen this on other systems with NVIDIA but not yet on a desktop with Intel iGPU. So this may be specific to NVIDIA.

My NVIDIA driver is running with "nvidia-drm modeset=1 fbdev=1" because otherwise I cannot properly run OBS recordings with obs-vkcapture.

chrome://flags/#ozone-platform-hint is set to "Default".