I completely agree. It seems that MIT App has recently updated their IDE which most likely caused this problem. Although it is not clear, if it is intentional or a bug.
I am creating a BLE app for Android10. And I have built a .apk file last July 17th which was able to scan and display discoverable devices perfectly. Today, I tried to re-build the same project, unfortunately it cannot scan nor display any available devices anymore. But if I re-install the .apk (BUILD:July17th), it works normally.