ItzStarrAD_
Comments
They are test blocks that showed up most likely you are a version behind *or ahead* of the version you created that world in. EX: you created the world in v1.18.30.03 and your using v1.18.30.04
if that is happening why don't you just limit your fps below 120 so that you don't stutter, because i think that's client side issues. And if it is client side mojang will most likely close this ticket and just ask you to contact customer support because they cant really do anything about this issue.
get a bigger screen its been that way for a while