In the client - singularities are displayed.
On the server - NULL singularities.
If you go to the single-world, then go to the server - it is displayed correctly.
Single:

Server:

If you went to the client and then to the server:

debug:
[Render thread/WARN] [net.minecraft.client.ClientRecipeBook/]: Unknown recipe category: [!!!com.mojang.logging.LogUtils$1ToString@7a0802ba=>java.lang.NullPointerException:Cannot invoke "Object.toString()" because the return value of "java.util.function.Supplier.get()" is null!!!]/avaritia:slime_singularity

I've tried to solve this problem, you can try this version.
Avaritia-Reforged-forge-1.18.2-1.1.1-universal.jar.zip

No, it's still the same.

I attach full debug from the client.
debug.log

Hi, here is more info.
my inv:

single:

server:

On the server, it doesn't matter which singularity you use to craft.

fixed