Just experienced this: Enemy Ki-100 dropped bombs, then crashed directly into my tank at 10:23. My vehicle was involved in the collision. Game registered it as “Ki-100 has crashed” and zero kill credit to me.
Bug report filed: Community Bug Reporting System
This is exactly why the Aircraft Crash Rewards system needs refinement (discussion here: https://forum.warthunder.com/t/rewards-for-crashed-aircraft/329965/336). Current system has exploitable gaps where aircraft deaths go uncredited despite direct player involvement.