1.12.2 Forge server timeouts when new chunks start loading

[Xzyio]

Started a Forge server (14.23.5.2859) on my home computer for Minecraft (1.12.2) using a custom mod pack.

Once I start moving quickly around the world to explore, the server timeouts. The console just stops responding to anything. I have to manually close the terminal. There are also no crash logs. I have attached the log and debug log here, which is exactly where it ends.

For further notes, when creating a new world, the server runs fine, but this happens only once the same world gets loaded for the second or more times.

Is there a mod that causes this? Is there some fix?

Edit:
My run batch file is "java -Xmx8G -Xms8G -XX:+UseG1GC -Dsun.rmi.dgc.server.gcInterval=2147483646 -XX:+UnlockExperimentalVMOptions -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M -jar forge.jar nogui". I originally used 12G for both Xms and Xmx, and the same issues occurred, so it is not caused by insufficient RAM.

Edited August 27 by Xzyio