game hang when getting in range of certain chunks (structures?)

[jlp1528]

Modpack

FTB Presents Direwolf20 1.21

Modpack version

1.7.0

Launcher

FTB App

Has the pack been modified

No

Log Files

debug - https://pste.ch/evidodusiy.md
latest - https://pste.ch/iqaqopawir.md
debug after friend was located near base, logged in, hung the server, timed out, but was finally able to log back in without issue - https://pste.ch/juvotileqo.md
latest - https://pste.ch/ajusagexiw.md

Describe the bug

When my friend gets in range of a certain chunk (structure?) the game hangs, eventually disconnecting him but leaving my "server" (open to LAN) running. The hang will happen again when he logs back in unless the game is set to peaceful.

Steps to reproduce

I noticed this with the coliseum until I set it to peaceful and my friend was able to break some redstone. Eventually a giant phantom with a skeleton spawned when I set it back to normal, which he killed and then broke the spawner. This time it's not the coliseum so I guess there's another structure with a corrupted entity or block causing this, but somehow peaceful fixes it so probably an entity.

Edit - peaceful is no longer resolving the issue. Which means whenever my friend connects to the server, the game hangs. So he can't play and we can't explore the area he is exploring.

Edit - I was able to resolve the issue by teleporting my friend away from wherever he was quickly. He had to log back in several times, each time hanging the game, but now he's okay. Please investigate this.

Expected behaviour

stop hanging my game while we're exploring

Screenshots

No response

Additional information

No response