Incubation Druid adapt value resets at end of turn (other adapt cards untested) [Fix in 4.1]

I was running Incubation Druid in AWR event. I noticed at the end of any turn in which he gained an adapt counter that it went away at the end of turn. Since his conversion effect is scaled by his adapt value this was rather bothersome. The +1/+1 seemed to persist, but his adapt went back to zero.