because of a race condition, the check for whether to regenerate a book entity can happen while the entity is unloaded, resulting in multiple entities per enchanting table. on the your-land server, i've found at least one enchanting table with 391 (!) book entities over the same table.
the fix for this is to not save the entity w/ the mapblock, and to instead re-generate it every time the block is loaded.
because of a race condition, the check for whether to regenerate a book entity can happen while the entity is unloaded, resulting in multiple entities per enchanting table. on the your-land server, i've found at least one enchanting table with 391 (!) book entities over the same table.
the fix for this is to not save the entity w/ the mapblock, and to instead re-generate it every time the block is loaded.