Modpack: Direwolf 20 v 1.2.0
Mod Version Refined Pipes 0.5.jar
Minecraft Version 1.16.4

https://pastebin.com/Dr6w7pjV

This happened after an interaction with Building Gadgets the builder, I tried to place the pipes with the tool, since they are all placed at the same time this error happened, I had to remove the mod completely because the issue would come back. I tried to remove the pipes via commands, I removed the mod, placed blocks in the spot the pipes were, and readded, it seems like this is something different that I couldn't really fix. Thanks for looking into it.

I play an Aternos server with the modpack Direwolf20 1.16 version1.13.0.mod version refinedpipes-0.5.1.jar
I have the same log ( https://pastebin.com/c2aVvtUq ).
Being a modpack, I can't delete or modify the mod.
mod version refinedpipes-0.5.1.jar

Thanks for the report, but there are no reproduction steps for me to do anything with...

Modpack: Direwolf 20 v 1.2.0
Mod Version Refined Pipes 0.5.jar
Minecraft Version 1.16.4

https://pastebin.com/Dr6w7pjV

This happened after an interaction with Building Gadgets the builder, I tried to place the pipes with the tool, since they are all placed at the same time this error happened, I had to remove the mod completely because the issue would come back. I tried to remove the pipes via commands, I removed the mod, placed blocks in the spot the pipes were, and readded, it seems like this is something different that I couldn't really fix. Thanks for looking into it.

I have experienced this as well in a single player world and I went into the server data and removed the refinedpipes-network.data and did exactly what you did and I still crash on load. If I remove the mod I load in fine but then recipes for the modpack im playing mess up because theyre required in some recipes. Im playing Stacia Expert Mode using refined pipes 0.5.