iPad stopping recording

A friend has the 11-Inch iPad Pro (2nd Generation) running 15.3.1 that he uses to video record meeting sessions. Twice this past month it has started recording and then almost immediately (15 seconds the last time) stopped. Other times it has worked properly (the last time for more that 30 minutes). He has it in airplane mode to prevent interruptions, and he has ample storage. Any thoughts on what could be the problem or how to fix it? Thanks.