This seems to be related to your name.
If it starts with an uppercase letter:
- on shutdown, you lose all your existing fleets
If it starts with a lowercase letter:
- on shutdown, your fleets still exist, but all their members have been forgotten (the ships are still there).
If you test in SP, make sure you don't use the same name twice or else you'll get mixed results
so use something like schema1 for lowercase example and Schema2 for uppercase example.