Getting rid of bees

Buttercup-3

Ok on blossom blast saga I'm in the 500s and I've noticed that my bee's disappear while playing. Not complaining at all I just wanted to know what is causing them to disappear 

KingsPinn

I know the bees move around, but I've never seen them disappear. 

Do you have a video of this happening or anything so we can see what causes it. Maybe it's something new?