In version OXCE+ v3.9a - the bug has not been fixed.
Let someone else test it. And that can at me somewhere an bug, which I can not identify in any way?
I can confirm it works in newest nightly.
I can unfortunately confirm it doesn't work in OXCE.
I do not recall this exact bug in Extended, if it existed it was probably fix already.
It's not fixed.
Attached a save to reproduce.
Steps:
1. load
2. end turn to get 2 kills with proxy
3. ctrl+D ctrl+K to kill remaining aliens
4. no experience and no kills
I'll have a look at it eventually, not sure when... if you have more time Yankes, feel free to investigate.