I think there was change recently
Before, when player come up before autumn, bearger spawned first day, but now he spawns at end of the autumn
I don't know what is bug, I am sure that bearger spawn time changed
Also when cut down trees using bearger, some logs or birchnuts don't drop 3 phase birchnut tree drop only one birchnut for example.
Sorry for poor English
Check bearger spawn time, and tree drops