Something is still askew - came home today and found our spa water level very low - this is what happened a couple days ago - This has happened before - I believe before this was caused by some valve being opened/closed inadvertently

My spa had a similar issue a few years ago.  I am almost positive it was a simple fix like a valve being in the wrong place.  The real question is does that owl keep ducks out of your pool?  I have an alligator that the ducks sit on.

I would check out our Video on Why does my Spa Drain when my Pump Shuts Off as well as our Guide on Why does my Spa Drain when my Pump Shuts Off  Normally it is a bad Check Valve You can view our purchase a replacement Check Valve by clicking this link - Replacement Pool & Spa Check Valves.