Planet population type change after revolt

Description

I do not know if this is a 1.25 bug, or a lurking bug from a n earlier version, as this is the first time it has happened to me.

During the AI turn/end of turn process, Ground combat starts between a before-unknown AI player and myself. AI has no ground troops, I have 10 Weapon Platforms. Combat ends saying I have conquered planet "Whatever-it-was IV"

This planet was a captured enemy planet, Oxygen atmo, with (Oxygen breathers) population 4000M/4000M (before). After the revolt, population replaced with a "clone" of my race (Hydrogen breathers) Population level: 4000M/1000M. I dumped all the "disloyal" ones into space (to make room for migrating Oxygen breathers)

This "clone" race has all the same stats as my custom race, except that the small race portrait is blank. They then began to migrate around my empire. So, I dumped them ALL into space. (BWaHaHaHa!)

A couple of turns later it happened again, different planet, Methane atmo. Same story.

The planet revolt is probably the cause of enemy intelligence projects (I didn't check) I just adjusted my defense percentage and have not had a problem since. In my experience, Planet revolts are to be avoided. In SE:IV, a newly formed Empire would have the same ship name file as the player, the AI would promptly use up ALL the names. VERY irritating. This doesn't seem to be the case with SE:V, but I rule with an IRON fist! OBEY THE FIST!