I noticed something that I think is unusual so I wanted to check in. Please provide your thoughts on what I experienced:

To grind for my Aeropress I moved my macro bar from 2 to 5 (running the grinder naturally, and with an empty chamber/hopper). I ground out about 1/4 - 1/2 pounds, then with the chamber empty and running, I moved the macro bar slowly back up to 2. I did this by stopping at each macro for a beat or two.

The next day, I loaded the hopper with my espresso beans and started to grind. Part way through the grind I heard the machine pitch change, and the shot was a gusher. Thinking about that pitch change, I didn't adjust the settings and made another shot and it was darn close to spot on. This leads me to the conclusion that the burrs moved closer together while under a load than the empty setting allowed.

Does this mean I should be adjusting the grinder full, and not empty?

Did your micro or macro sliders move during grinding? If so, Baratza will send you shims to keep them in place. Moving from setting to setting on the Vario is unfortunately not very repeatable.

I agree the shims are a must. I was having the same problem when making the occasional pot of drip coffee. What worked when returning to previous setting was to move the macro lever 1 or 2 notches finer while the grinder is running then back to desired grind. Usually the next shot will not be perfect but close. After that it should be OK. Try and avoid chasing the grind you'll make yourself crazy. Sometimes Varios need a shot or 2 to settle back in.

I installed the shims about a year ago and I agree they are a must. I didn't see any motion on the micro which I leave alone when grinding coarser.

I have experienced that 2G isn't always 2G and that the tick marks are guidelines. But the fact that it took a bit to settle in was not what is expect.