Flatpak: GUI isn't rendering

[sevu11]

I have installed the Bridge app via Flatpak and its starting but no GUI is rendered.

[sevu11]

[Mx-Angel]

Having the same issue:
System info:
Distro: Arch Linux
Kernel: 6.10.6-arch1-1
CPU: 5600x
GPU: RTX 3070
GPU Driver: 560.35.03-2

[Jonorizabal]

Same issue as well.
Distro: Universal blue aurora
Kernel: Linux 6.11.3-300.fc41.x86_64
CPU: 3600
GPU: 1070Ti

[AtmosphericIgnition]

Same issue here.

Distro: Arch Linux
Kernel: 6.12.10-arch1-1
GPU Driver: nvidia 565.77
DE: KDE Plasma 6.2.5

$ flatpak run ch.protonmail.protonmail-bridge
Failed to initialize sentry
INFO[Jan 24 20:52:07.592] bridge-gui starting
INFO[Jan 24 20:52:07.592] Using Qt 6.4.3
INFO[Jan 24 20:52:07.601] lock file created /home/user/.var/app/ch.protonmail.protonmail-bridge/cache/protonmail/bridge-v3/bridge-v3-gui.lock
INFO[Jan 24 20:52:07.601] bridge-gui executable: /app/lib/protonmail/bridge/bridge-gui
INFO[Jan 24 20:52:07.601] Command-line invocation: --session-id 20250124_205207574 --launcher /app/lib/protonmail/bridge/proton-bridge
INFO[Jan 24 20:52:07.601] New Sentry reporter - id: iQyr4nETZAMyb4JSxZz91HFg+mP+ejeAHTv/wdu/A/M=.
DEBU[Jan 24 20:52:07.619] Bridge executable path: /app/lib/protonmail/bridge/bridge
INFO[Jan 24 20:52:07.619] Launching bridge process with command "/app/lib/protonmail/bridge/bridge" --grpc --parent-pid 9 --launcher /app/lib/protonmail/bridge/proton-bridge --session-id 20250124_205207574
INFO[Jan 24 20:52:07.619] Retrieving gRPC service configuration from '/home/user/.var/app/ch.protonmail.protonmail-bridge/config/protonmail/bridge-v3/grpcServerConfig.json'
INFO[Jan 24 20:52:07.719] Connecting to gRPC service
INFO[Jan 24 20:52:07.735] Tray icon is visible: true
INFO[Jan 24 20:52:07.738] Connection to gRPC server at unix:///tmp/bridge2731. attempt #1
INFO[Jan 24 20:52:07.742] Successfully connected to gRPC server.
INFO[Jan 24 20:52:07.742] Client config file was saved to '/home/user/.var/app/ch.protonmail.protonmail-bridge/config/protonmail/bridge-v3/grpcClientConfig_0.json'
DEBU[Jan 24 20:52:07.742] checkTokens()
INFO[Jan 24 20:52:07.742] gRPC token was validated
INFO[Jan 24 20:52:07.742] Connected to backend via gRPC service.
DEBU[Jan 24 20:52:07.742] version()
DEBU[Jan 24 20:52:07.742] EventStreamReader started
DEBU[Jan 24 20:52:07.742] goos()
DEBU[Jan 24 20:52:07.746] logsPath()
DEBU[Jan 24 20:52:07.747] licensePath()
DEBU[Jan 24 20:52:07.747] mailServerSettings()
DEBU[Jan 24 20:52:07.748] getUserList()

[AtmosphericIgnition]

This seems to be some kind of issue with the Wayland front end. When I revoke the programs ability to use the Wayland socket, forcing a fallback to xwayland, the GUI seems to render properly.
The version from the Arch Linux repos runs just fine for me (Qt 6.8.1). Perhaps Proton building software against an unsupported, almost 2 year old version of Qt (6.4.3), could be the cause of the issue.