I've figured out you're allowed to use the Badlion client however i still get kicked for using a modified client? I'm only using the mods that are allowed so i don't understand.. I've seen someone say it's because of the anti cheat or something. I get an average of 13-14 cps when fighting if im trying and sometimes my hits fully won't register, until my recent testing, after i hit them with something other than a sword (this is in arenapvp) my hits will register again. After that i'll probably get kicked again for using a modified client so im quite confused.
The anti cheat is quite sensitive and pulls back if you travel a certain amount of blocks per second, it will also kick you if you get over 9+ cps for having a modified client. All you can really do is place a bug report with the screenshot of the kick code so they can attempt to fix the issue and develop the anti cheat.
Not much otherwise you can really do to prevent getting kicked as this happens to many players. Question Answered Thread Locked