I have a similar (?) bug (?) in 5.53 :
- order a TF with 1 jump ship and a survey vessel to 'standard' transit some jump point (unexplored, btw).
- the TF completes its orders on August 1st, 2048.
- split the TF : the jump ship is set to 'survey nearest survey location' (its a gravsurvey scout), the other ship is set to 'survey newt 5 system bodies' (its a geosurvey ship).
- click the 30 days (auto-turns off) button
- the game goes to September 1st, 2048 and... both ships are still waiting at the JP.
The next move will be OK however so the ships are not stuck : they acknowledge their order. Only, they are waiting a full time increment before beginning to apply it. And a 1 month delay seems far too long to be a honest delay