Timing question.

[supramacist]

Today I finished reinstalling all of my power steering pump system.
I janked it all out and cleaned it up nice again. Loaded the pump.

Bled everything till I was convinced that I had no more bubbles. Took it for a few drives around the block. Came back watched it. Let it run for a half an hour. All's well. Shut her off.

30 minutes later the wife gets home and I ask her if she wants to go around
the block before I park it for the day.

When I get back. The car is idling high. From 900 to 1k rpm's. Up to 2k rpm's. I break out the timing light. And the timing has jumped forward By about 15 degrees I would guesstimate.

What could have caused this? Did I miss something? The crank pulley nut is tight. For that big a jump I would think something with the dist cap teeth internally nearly had to skip if I didn't know any better. I'm hard pressed to think the timing belt skipped. Hard pressed.

Any thoughts or comments would be greatly appreciated.
Thanks for reading.