Savegame corruption, tourists visiting station contract

[JCU0]

Savegame corruption is always a very frustrating problem. Tracking down the issue leads me to WBIContractVesselTour contracts. My game is heavily modded: Outer planets, TAC LifeSupport, Kerbal Construction Time, ship parts mods, all from CKAN. Game version: latest 1.12.2.

For now, I have the savegame files just before corruption and just after it happens. In a ship I have tourists returning home from Minmus station, contract is marked as finished. I have another passenger ship (atmospheric shuttle) floating the first ship. If I dock them, the game becomes corrupted. If I undock them or transfer crew, or doing almost anything else, game is still corrupted. But if I successfully transfer tourists, land them and recover all in one go without switching to KSC or another vessel, then my game becomes uncorrupted again.

Symptoms of corruption:

1. Inability to switch to corrupted ship (with returning tourists). Game is stuck trying to load a ship and spamming tons of NullPointerException messages to the log. All other ship outside the physics range from corrupted one are safe and can be piloted.
2. In my astronaut complex I see tourists disappeared from Assigned tab and I see a crew limit notification (MAX=12), but KSC is fully upgraded, no limits should apply.
3. In my savegame file ROSTER section I have tourists disappeared, but in the corresponding FLIGTHSTATE/VESSEL/PART section I see them as crew members.

Also, this type of contract has some bugs:

1. It's "slightly" cheaty: about 15 000 000 credits reward just for a simple midgame Minmus/Mun mission.
2. "Return to Kerbin" contract task is marked as finished just after tourists are ready to launch, the whole contract is considered complete when tourists is still visiting their tour target. Maybe it's the source of savegame corruption problem.
3. Minor inconvenience: a tour contract can't be collapsed inside contract info panel when the tour time is ticking.

Savegame files here: just before docking (and corruption) and just after (can't switch to the ship).

• Ship is named Bus.
• Last finished contract is for tourists visiting station.
  saves.zip

[JCU0]

After reading your code, I think deleting tourists while they are not recovered to KSC is generally a bad idea. Because even when a craft is landed on Kerbin, it may stay there without being recovered, waiting, for example, a helicopter.