Alpha 4.25 is now available. This patch fixes a bug with retreating fleets introduced in 4.23. You should probably download this version for the fix. You can download the latest version from itch.io:
Remember that you can report bugs and discuss the game on Reddit at http://www.reddit.com/r/rotp
Retreating fleets – A validation fix in 4.23 exposed some out-of-order code in the fleet retreat logic, which manifested with two symptoms: retreating fleets were not automatically launching to their target system, and fleets retreating to empty systems would DISAPPEAR. Problem is fixed.
Thanks again to all of the testers for their great feedback!