Hi @crypto.piotr,
are you aware that you are upvoting the posts by @steemengineteam?
The got the keys of ~2000 accounts, they produce 1-2 bot-generated posts a day and use the keys to upvote them.
You can counter this by either changing your upvote into a downvote everytime, or by changing your master key (e.g. on the steemit wallet).