Sounds like it happend on the start of descent. Was it a classic perhaps?
The old HP bleed valve blocked unnoticed and then the other HP bleed falling over. Thrust up a little, LP's pick up the slack, problem solved, descent normal-ish, passengers non the wiser, never trained but thats what experience does for you but who needs experience now days. Don't know if this problem persisted on the 800's.
Guess we'll hear if it was something more serious.
All safe - all's well.
