Describe the bug
Game crashes to an error screen with the options to return to server select or view the folder containing the crash reports.

To Reproduce
None. It appears to occur at random even when not directly interacting with the Theurgy content. I am in the same game chunk each crash.
Current Theurgy activity: 2x Distiller, 1x catalyst, 1x incubator and attached blocks, 2x calcination oven, 1x cauldron, 1x accumulator and attached vat. Numerous attached insert/extractors/wires. Utilizing base game hoppers and AE2 for item/fluid transport. See image for specifics.

Expected behavior
N/A. Was checking inventory/walking in the chunk.

Screenshots
N/A

System (please complete the following information):

• Theurgy Version: theurgy-1.21.1-neoforge-1.60.0.jar
• OS: Windows 10 Home / Bisect Hosting private server
• Minecraft Version: 1.21.1/NeoForge
• Modpack Link and Version, or list of mods: Craftoria 1.20.3, unmodded further.

Additional context

disconnect-2025-05-24_11.35.06-client.txt
disconnect-2025-05-23_10.03.23-client.txt

I'm having the exact same error. I'm running on Windows 11 Pro on Craftoria v1.21.2 and Minecraft 1.21.1/NeoForge. The server is a private server on my own machine. The disconnects happen sporadically every couple of minutes.

disconnect-2025-06-26_00.44.22-client.txt

This is caused by some other mod - as yet unidentifed - that uses a mixin or otherwise modifies how vanilla/neoforge entity synced data works.

-> "Invalid entity data item type for field 10 on entity FollowProjectile"
The follow projectile is the entity used by theurgy, but theurgy does not make any modifications to the synched entity data.

If we can find out with which mod the incompatibility exists I can get in touch with the author to make sure that either the mod does not affect the FollowProjectiles any more, or that I make changes on my side to be compatible with their changes.

Most likely it is some sort of performance optimization mod

I am closing this as stale, but please ping me if you can identify the mod that causes it in connection with theurgy.

Heya, the issue seems to be related to Apotheosis (might even be caused by Apotheosis itself). It appears that it tries to update the "follow porjectile" with it's data when the entity is already gone again, resulting in the disconnect. I compared the mods from my modpack, ATM10 and the mods from Craftoria given the provided log by OP. I removed Apotheosis and the issue did not appear anymore. Am still testing around rn but I am quite positive that it is an Apotheosis thing.

Edit:
Shameless belated ping @klikli-dev