Whenever I order my ships to Retreat in this match, they disappear from the map without a trace.

Save File: AutoSave 293.zip

Had this happen three or four times in a game last night.  In every case the retreat happened in a different constellation from my home one, so not sure if that was a factor or not.  I did have a friendly system there though, in at least one of the cases, though in all cases there were other faction systems between the battle and my system.  In all cases the post battle screen clearly showed my ships were still in one piece, but they vanished from the map never to be seen again.