PyWinAuto in exe (PyInstaller) on Citrix can't find window, from python itself works like a charm

Question

I have a pywinauto application that triggers a search in Notepad (for testing purposes).

This works excellent in a regular Windows enviroment. (both running directly from running the python script stand-alone, as from the pywinauto-packed exe).

When I run this in an Citrix environment, pywinauto seems unable to find the windows when running from the pyinstaller-exe. When running directly from python, it does work correctly.

I couldn't find limitation in the pyinstaller documentation, as that states that it works with pywinauto.

(This is using Python 3.10)

This is the error from the .exe:

Update

Building like this (with splash screen)

pyinstaller.exe --noconfirm --noconsole --paths ./venv/Lib/site packages/ --splash splashscreen.png ./main.py -n notepadopener

Seems to make it fail. Building without splash-screen works fine:

pyinstaller.exe --noconfirm --noconsole --paths ./venv/Lib/site packages/ ./main.py -n notepadopener

Update 2

It seems this piece of code in the main.py, which should hide the splashscreen, causes it to fail.

# Hide the splash screen after one second
if '_PYIBoot_SPLASH' in os.environ and importlib.util.find_spec("pyi_splash"):
    import pyi_splash
    sleep(1)
    pyi_splash.close()

Update 3

It seems adding a sleep after the .close() also solves the issues..

# Hide the splash screen after one second
if '_PYIBoot_SPLASH' in os.environ and importlib.util.find_spec("pyi_splash"):
    import pyi_splash
    sleep(1)
    pyi_splash.close()
    sleep(0.5)