Bug: UI is not working in VST2 version

[starry-abyss]

Describe the bug

I can run standalone, but in VST2 the UI is broken.

Steps to reproduce

List all steps to reproduce the behavior:

1. move *.so of traKmeter VST2 plugin to ~/.vst
2. start Carla
3. press "Add Plugin" in Carla
4. double click on traKmeter (stereo) - it should be hosted now
5. go to "Rack" tab
6. right click on Carla-made UI of trakMeter
7. select "Show Custom UI"

Expected behavior

I expect native traKmeter UI to be shown, just as in standalone version.

Screenshots

This weird rectangle below in the middle is traKmeter VST2 UI:

Environment (please complete the following information)

• OS: openSUSE 15.3 64-bit
• DAW: Carla 2.1.1 (in this issue I'm using it to connect JACK signals to traKmeter)
• Plug-in: TraKmeter v2.4.7 VST 2 (64-bit)

Did you compile TraKmeter yourself? no

Tool set (if you compiled the plug-in yourself)

Didn't compile

Additional context

I also tried hosting it Renoise, and the UI is also completely broken there.