dTube did it, too. I just unfollowed them. It may be the second time I've unfollowed, or else it was dMania I had to unfollow. I know I unfollowed one of these platforms after signing up to use it. Busy maybe?
Anyway, it's a cheap and underhanded way of going about getting followers for sure.
I'll check my followers list again and see if dtube comes back.