iceberg vers: Iceberg-1.20.1-forge-1.1.13.jar
tooltip version:
LegendaryTooltips-1.20.1-forge-1.4.5.jar
mc 1.20.1
forge 47.1.3

error occurs when using a grindstone and looking through jei and ultimately crashes with:
java.lang.IllegalArgumentException: The class com.anthonyhilyard.iceberg.renderer.VertexCollector$1 does not implement interface VertexBufferWriter, which is required for compatibility with Sodium (see: CaffeineMC/sodium#1620)

here is the full crash report for easier reading: https://mclo.gs/T5SoqPW

Setting render_item_model to "NONE" seems to be a suitable temporary solution.

Replicated on Forge 47.2.20, Embeddium 0.3.3

Cannot Reproduce.
Embeddium 0.3.4
NeoForge 47.1.98

and its happening regardless of what item im hovering over

Having the same issue. If you have Sodium or Optifine it crashes as soon as you try to make or upgrade an item in any way.

Having these issues on the Fabric version.

Issue also occuring to me. Playing on Fabric 1.20.1 with Sodium 0.4.10

Same issue with Forge 47.1.47 and Embeddium 0.1.4

you shouldnt need a reason to be higher than 47.1.3 for any mod

Same issue with Forge 47.1.47 and Embeddium 0.1.4

Oh ok, I'll never update Forge again.

Oh ok, I'll never update Forge again.

reason for that is bc the entire forge dev team is now neoforge. old forge is now solely run by the owner

Oh ok, I'll never update Forge again.

Devils is correct. Forge above 47.1.3 is completely broken. Forge is essentially dead now.
Check out NeoForge or start moving over to Fabric for mods.