Huge experience boost

[Breschau]

Is this a bug, or have I missed an event somewhere? :

I loaded a saved game and remembered I'd sent out a Harvester to scout and spread disease. When I checked on it, I discovered it was in the hall of fame and had 5 stars of experience.

I looked in the hall of fame and it's sitting there with 25705 xp! It has zero kills and has never, to my knowledge, been involved in a battle.

(the next two places are taken by Orion and Bogus.. best non-indep place is a Ctis hero with 20 kills and 273xp)