Interesting Invasion Notice Under 2.3.504549

I am playing as the Xeloxi and, during the transition between the end of one turn and the beginning of another turn, I got the notice shown below.  Apparently, one of my transports is invading one of my planets.  How does that happen?

Here is a link to a save file that will let you see this happen:

https://www.dropbox.com/scl/fi/8cqv8e22wexdlh7bro06l/Attacking-Myself-Under-2.3.504549.GC4Sav?rlkey=os091d9kzo0wssn2kmvbu3c91&dl=0

The steps to recreate are:

1. Load the save file.  You should be at the end of a turn.
   1. If you go to the planet "Alula Borealis I" which is owned by the Yor (near the top of the sector) you should see that I have a transport that should automatically attack the planet as part of my "end of turn" moves.
2. Hit the icon to move to the next turn.
3. You should now see the message shown below.