iPad alarm sound occurs when receiving a call on iPhone
This is a recent development that has happened twice. I get a call on my iPhone. After the call, I hear a faint "alarm" sound going off somewhere. I trace the sound to my iPad in another room that has the volume turned off. The iPad is connected to my phone so that I can answer calls on it if I want (and has been this way for years). In order to stop the alarm, I have to disconnect the charging cable and reinsert.