When I win a battle, I  can get some post-battle loot based on the enemy I killed in battle. But when fighting against Beastmen and Tomb King, sometimes I cant get any loot. 

If I manage to kill the lord in manual battle, I can get like 2k loot, but if I fail, I get no loot. I'm not sure whether it's by design or not, anyway it looks a bit strange for me.

This is a auto-resolve result against beastmen. The lord is killed, we got 1760 loot, the one on the left of exp gain. 

Then this is a manual battle result. I didnt kill the lord, then we got 0 loot. I also checked the finance tab, it also said I got 0 loot this turn. (Savefiles uploaded. It's a hard battle,  you can turn to easy battle difficulty to test it)

That's strange isnt it. Is it a bug or not?

BTW here's another one, against Tomb King. I found If I kill the tomb king lord during warden's cage, I also get 0 loot. This screenshot is with some minor visual mods that altered level icons or so, though. I'll try to get one without mod later. (the uploaded one is mod-free)

Guess the 2 races have the same problem, since they're both free from recruitment cost. May you have a check.