Does twitter make an error on whose following you?

[Lily Rose]

Can twitter make an error on whose following you ? Someone I know but don't really talk to is not on my follower list but when I went onto his page it says ''(his name) follows you'' yet he isn't on my follower list ? I checked four times and every time I go on his page it says he's a follower. Can this be an error or does he actually follow me ?
Adam H - I don't fancy this guy lmfao. Its that he rude and horrible to people on twitter and don't want to be subject to this. Actually worried he can view my tweets !

[Adam H]

Stop it. You sound desperate.

[Dddd]

Block him