What were you trying to do that didn't work?

Use GUI applications within GNOME Shell with normal window decorations. 

What is the impact of this issue to you?

More difficult desktop interaction, Visual inconsistency 

Please provide the package NVR for which the bug is seen:

gnome-shell 40.10-21.el9

How reproducible is this bug?:

Varies per application

Steps to reproduce

1. Install Chromium Flatpak from Flathub
2. Allow popup for a website and trigger a popup

or

1. Install Discord Flatpak from Flathub
2. Launch Discord

Expected results

Normal thickness of window decorations

Actual results

Thin window decorations