Would you be able to upload the PNG image you used for the icon? That way I can see what’s going wrong there.
Sure, here it is below:

Thank you so much! The image is saved as 48-bit, while the software expects 32-bit. Resaving it using any image editor as 32-bit solves the issue, however of course I need to catch this in my software and either fix or show a warning. Thanks for letting me know!
Edit: I fixed the issue and it'll now work, it will be added in the next update!