'Network Protocol Error'

[Qxblx]

According to the disconnect log:
Invalid entity data item type for field 8 on entity class_1542['Air'/10715949...]
old=minecraft:(class java.lang.String), new=2 minecraft:dirt(class net.minecraft.class_1799)

Essentially meaning the client received mismatched packet (String being a Dirt ItemStack), which triggered the IllegalStateException, and the bundle packet (clientbound/minecraft:bundle) from the server was malformed or translated incorrectly.

The main reason might be ViaFabricPlus, translating packets between the client and the server.

[Qxblx]

IMPORTANT
Without ViaFabricPlus, I tried again, and the logs were nearly the same, except the new log said:
old=minecraft:(class java.lang.String), new=1 minecraft:dirt(class net.minecraft.class_1799)

So in both cases, the client is expecting a String for entity data field 8 on class_1542['Air'], but it instead receives a Dirt ItemStack. The only thing that changes is the packet’s internal data type ID (1 vs 2). Additionally, it happens whenever the server tries to sync metadata for a certain “ghost” entity near x=-14481, y=60, z=-14243.

POTENTIAL SOLVES
Remove suspicious entities in the area:
/kill @e[x=-14481,y=60,z=-14243,distance=..3]

List nearby entities for debugging:
/execute at run data get entity @e[distance=..10,limit=10,sort=nearest]

Unload/reload the chunk / force save (plugin dependent):
/chunkborder fill -14481 ~ -14243 1