So this error randomly comes up if you run around the world... and then the server crashes because of lag.

�[m>
[23:44:24] [Server thread/WARN] [FML]: MrTJPCore loaded a new chunk [-50, -125] in dimension 0 (overworld) while populating chunk [-46, -126], causing cascading worldgen lag.
�[m>
[23:44:24] [Server thread/WARN] [FML]: Please report this to the mod's issue tracker. This log can be disabled in the Forge config.
�[m>
[23:44:24] [Server thread/WARN] [FML]: MrTJPCore loaded a new chunk [-51, -126] in dimension 0 (overworld) while populating chunk [-46, -126], causing cascading worldgen lag.
�[m>
[23:44:24] [Server thread/WARN] [FML]: Please report this to the mod's issue tracker. This log can be disabled in the Forge config.
�[m>
[23:44:24] [Server thread/WARN] [FML]: MrTJPCore loaded a new chunk [-50, -128] in dimension 0 (overworld) while populating chunk [-46, -126], causing cascading worldgen lag.
�[m>
[23:44:24] [Server thread/WARN] [FML]: Please report this to the mod's issue tracker. This log can be disabled in the Forge config.
�[m>
[23:44:25] [Server thread/WARN] [FML]: MrTJPCore loaded a new chunk [-51, -128] in dimension 0 (overworld) while populating chunk [-46, -126], causing cascading worldgen lag.
�[m>
[23:44:25] [Server thread/WARN] [FML]: Please report this to the mod's issue tracker. This log can be disabled in the Forge config.
�[m>
[23:44:25] [Server thread/WARN] [FML]: MrTJPCore loaded a new chunk [-50, -124] in dimension 0 (overworld) while populating chunk [-46, -126], causing cascading worldgen lag.
�[m>
[23:44:25] [Server thread/WARN] [FML]: Please report this to the mod's issue tracker. This log can be disabled in the Forge config.
�[m>
[23:44:25] [Server thread/WARN] [FML]: MrTJPCore loaded a new chunk [-51, -125] in dimension 0 (overworld) while populating chunk [-46, -126], causing cascading worldgen lag.
�[m>
[23:44:25] [Server thread/WARN] [FML]: Please report this to the mod's issue tracker. This log can be disabled in the Forge config.
�[m>
[23:44:29] [Server thread/WARN] [FML]: MrTJPCore loaded a new chunk [-48, -123] in dimension 0 (overworld) while populating chunk [-46, -126], causing cascading worldgen lag.
�[m>
[23:44:29] [Server thread/WARN] [FML]: Please report this to the mod's issue tracker. This log can be disabled in the Forge config.
�[m>
[23:44:33] [Server thread/WARN] [FML]: MrTJPCore loaded a new chunk [-45, -123] in dimension 0 (overworld) while populating chunk [-46, -126], causing cascading worldgen lag.
�[m>
[23:44:33] [Server thread/WARN] [FML]: Please report this to the mod's issue tracker. This log can be disabled in the Forge config.

Volcanoes are big, nothing we can do about this sadly, if your server crashed please provide that.

What you mean with that?

He is asking for the crash logs. There may be a way to make volcano generation better so that it only generates if all required chunks are already there instead of forcing them to generate. It will be explored in the future. However, it is not a priority right now. If its causing lag then disable them for now.

How to disable it @MrTJP

This really isn't an issue, Volcanoes are just big, 1.13 worldgen has been rewritten, so this will be addressed then.

How to disable it @MrTJP

Setting

    B:"Volcano retrogen"=false
    B:Volcanos=false

in ProjectRed.cfg both to false, like in the example above, will stop Volcanoes from generating.