Originally, I had a longer message that explained that the issue would be a minor inconvenience if not for the clearlagg plugin (because I seem to always die right before the countdown begins and the time for re-connecting cuts it very close), but then I got the "trouble connecting to server" page when trying to post it and re-made the post in a bullet-point level of detail.
I have experienced this issue before on another server, but it was also a different mod pack. In both cases, they were servers started by members of the community for the vanilla server I play on, and I don't play on other servers because--no offense intended towards other players--I just don't trust that my builds won't be griefed and/or looted in communities where I don't have the same level of familiarity.
I have tried moving, but that doesn't work. Watching the coordinates on the mini-map, I see that the y is dropping in the same manner as a new ssp world trying to load the chunks for the first time. I don't know if it helps in diagnosis, but the launcher console does not note anything beyond the fact that I have died.
f3+a has no impact on the situation. I don't know if it has any relation to the situation, but I do have some lag with the server. It is noticeable in that sometimes blocks re-appear after being mined, but not so bad that it is impossible to fight mobs.
My main thoughts were that it is 1) one of the mods interfering with the world data or 2) one of the plugins preventing data packets from being properly sent and received..
