After a failed campaign, where significant fighter losses were taken, a fleet was moved back to earth to restock losses and rearm.
After manufacturing new fighters and assigning them to the relevant carriers in subfleets, the Ship List of these subfleets were not updated from when the battle has been taken place. - By that, I mean the ships assigned to the Ship List - the information viewed in the Ship List seems relevant.
Having detached the subfleet to see if I could update the window that way, the new fighters - newly manufactured - got moved from squadrons in the carriers to the general fleet.
Moving them back in to their relevant carriers and detaching to recheck - all fighters now ran away from their assigned squadrons to squat in the general fleet.
To refresh, there is the dedicated button, in the row of buttons at the bottom of the window.
Or, you can reselect the player’s race at the top of the window.
Which command have you issued to the fleet(s) to join again the parent fleet(s)?
Just to confirm what I think I am seeing. You created a sub-fleet, then dragged ships into it, where the parasites retained their squadron assignments. Then you detached the sub-fleet, which became a fleet, but the parasites lost their squadron assignments, although they were still on their motherships?