setting of notification time fails in App

My outdoor cameras should record around the clock. Until a few days ago, this was working fine. In the settings of the app (iPhone, iOS 18), the notification time was set from 00:00 to 23:59. NOW, it is set to "from 01:00 to 01:00". When I try to set it back to "from 00:00 to 23:59", I cannot save it, and the time resets back to "from 01:00 to 01:00". What should I do? Or is this a bug in the app?