Hi AlexPawlak,
I have seen similar issues on other threads. It seems that when running the Flow mobile app on Windows phone, there might be duplicate notifications for the action “Send me a mobile notification”.
Do you have other phones? If you have iOS or Android, please try it on your side to see if you would still get duplicate notifications.
I will try to report this issue on my side and back to you once I got any response.
Best regards,
Mabel Mao