So this is kind of an awkward situation, but here it is.

Dathomir, Ord Mantell, Ilum, and Dantooine are all NEUTRAL

Mygeeto and Mandalore are IMPERIAL.

The Imperial player is holding probe cards for Ord Mantell, Illum, and Dantooine.

Mygeeto contains 1x AT-AT, 1x Stormtrooper, 1x TIE fighter, and 1x Star Destroyer.

Mandalore contains 1x Mon Calamari Cruiser.

The rebel players first action of the turn is to attack from Mandalore into Mygeeto. The Imperial player drops a leader in to draw combat cards. After the first round of combat, the imperial player retreats.

Legally the imperial player has to retreat to an imperial location if able, which in this case isn't an option since you also cannot retreat to the planet which you were attacked from. Given my probe cards and state of the board, I am 99% sure that the rebel base is in Dathomir.

Dathomir is a neutral planet with no enemy units in the system making it perfectly legal for a retreat.

If I retreat and land ground troops onto Dathomir, the rebel player has to then reveal his base which the triggers another combat.

I've got about 17 games under my belt and this is the weirdest thing that has happened so far.

Is this a correct interpretation of the timing and interaction of the retreat rules and revealing the rebel base rules?

(In this situation I happened to be sure that the base was on Dathomir, but this could just as easily happen with dumb luck. An imperial player could be in a situation where he retreats and accidentally stumbles upon the rebel base)

Right on all points!

It's a surprising and slightly amusing scenario, but I see no problem with it. And if the Imperials are already in a position of retreating, they probably aren't as much of a threat to the rebel base as they would like to be.

It's like running into a cave for safety and then finding out about the bear. The listing on TV Tropes must be enormous.