Un-Modded Realm Gives Players Unplayable Super-Speed

hello! an acquaintance previously posted a bug report, and it was flagged as a “duplicate.” it, in fact, was not. our realm is an un-modded realm with no add ons. any new player that joins has insane super speed, to the point where the game is entirely unplayable. the realm we created was intended for all our friends to play on, and it upset us that our friends cannot join an play. i would appreciate if you all could help us fix this as soon as you can. thank you!