If a mod uses the API to register inject permissions for a block, injectEssentiaIntoContainer will void essentia once the block is full.

This is due to getContainerStoredAmount assuming a stored amount of 0 for non-vanilla Thaumcraft blocks, and injectEssentiaIntoContainer not checking for a non-zero return from addToContainer.

A workaround is for the block to return false to doesContainerAccept when full, but that is not possible for all blocks, and will still result in voiding excess essentia if the export bus sends more than the block can hold.