[Bug] 1.90 View Battle for Ship Gravyard results in incorrectly lost fleet (with Savegame)

Repro steps

1. Load save game (Terran Carrier Test.CG3Sav)
2. Select fleet "Terrans Fleet 17162"
3. Move to adjacent Ship Graveyard anomaly
4. Yes - engage them in battle
5. View Battle
6. Battle Summary indicates pirates lost 2 units, Terrans lost 0 units
7. Return to strategy view

Expect: Terran fleet still alive, anomaly explored
Actual: Terran fleet destroyed, anomaly intact

Note: Selecting Quick Battle results in expected behavior

Savegame link:

https://1drv.ms/u/s!AjQNX_0pj-ibg7xHlAUxAyiLmXovCg