Trees randomly turning very dark then back to normal on Shelter Woods

sleepy_knight

I have found this bug twice so far, both times on Shelter Woods and only while playing survivor.

Randomly a few trees would turn almost fully black (but still keep some texture), stay that way for a few moments (about 10-15 seconds) then they fix themselves. Both times only my camera was moving, the character was still. Lighting issue maybe?

Platform: steam