GTK wobbling/moving weird, when resized

[Tornado300]

Im writing a GTK UI (running on a layer) using Fabric (ffpy.org), but when i use a revealer and reveal it (let it expand) the other boxes around the revealer start to resize. I deactivated the layer animations and also tried deactivating all animations, but nothing helped. I talked to the Dev of Fabric and he is sure that it is a Hyprland issue. I also tried the same UI on sway and there it works fine. Also when the other boxes resize they dont emit a resize request to GTK so its not really resizing. only visually.

This is the hyprland version i use:
Hyprland 0.49.0 built from branch at commit 9958d29 (version: bump to 0.49.0).
Date: Thu May 8 20:15:18 2025
Tag: v0.49.0, commits: 6098
built against:
aquamarine 0.8.0
hyprlang 0.6.3
hyprutils 0.8.0
hyprcursor 0.1.12
hyprgraphics 0.1.4

for any further infos please ask.
Thanks