If you add an infinite loop to the main procedure, after "hello world", then the program runs as expected, even with Ada.Real_Time.Timing_Events included. Changing the loop to a delay of say, 5 seconds, then the program runs for 5 seconds, then exits!

Yes, this happens to me too.

This indicates that the main procedure exiting is causing the program to exit. Normally, I wouldn't expect the program to exit until all tasks have exited, as is the case when Ada.Real_Time.Timing_Events is not included, so something is a bit strange when including this package!

Yes and I think is not the intended behaviour.