Exactly what it says on the header. Happens consistently through the entire Homeworld: Remastered campaign as well as in AI skirmish mode.
Steps to reproduce: In any game mode, set a carrier or Mothership to “remain docked” and dock any ship with a group assigned. Save and then re-load the game; when you launch the ship, its group number will still appear when it is selected manually, but you will be unable to select it via the group hotkey. Additionally, if all of the ships in a group are docked, then the group number at the bottom of the screen will no longer be filled in when the game is loaded.
I’d classify this as a minor irritation, mostly because I tend to save my playthroughs at the end of each mission, after completing my post-mission construction and organization (including docking all of my strike craft where I need them to deploy at the start of the next mission). I’ve had to save before docking any ships, because otherwise the game will auto-launch them all when I jump, having deleted all of their group assignments, resulting in unnecessary hassle at the beginning of the next mission.
I’d also like to take this opportunity to request a stable “remain docked” function that does not reset to “auto-launch” when jumping between missions. This old HW2 design oversight makes it nearly impossible to bring strike craft into certain Classic missions without taking losses almost immediately, before having any chance to recover said strike craft to more defensible positions (8 and 12 deposit launching fighters and corvettes into groups of swarmers and gravity wells, respectively). Players should never be put in a situation where they cannot avoid losing ships, especially when the only existing workaround is to retire them at the end of the previous mission.