UPDATED REPORT FOR NEW TITLE:

It appears that changing any client game setting, regardless of whether or not they are to be sent to the server, are issuing a "Client Information" ( https://wiki.vg/Protocol#Client_Information_.28play.29 ) network packet. Changing a slider-based option (ie. Menu Background Blur or FOV Effects), combined with high game framerate, can cause this packet to be flooded towards the server. This may cause servers with anticheats that have anti-spam measures to kick a player as they are editing their game options. I have attached footage of this packet flood happening on a local server running Spigot for Minecraft 1.20.6, though it is still present in 1.21. I am unaware of whether or not earlier versions also have this bug.

ORIGINAL REPORT:

"As the title suggests, I believe game settings that are changed using a Slider cause an unintended spam of network packets. I have only been able to observe this behaviour while modifying Accessibility-related game settings, ie. FOV Effects, Menu Background Blur, Glint Strength/Speed, etc. Non-A11y settings such as View Distance or Fullscreen Resolution do not seem to trigger this packet spam. It also seems to be at least semi-dependent on frame-rate, as the send-rate increases the more FPS you have in game. While this seems to be mostly harmless, it does have the potential to trigger anti-spam checks in server anticheats, thus resulting in a user being kicked while configuring their game."