getFakePlayer is using dimensionType, but should be using the levels dimension
As there can be multiple dimensions with same type in modded, so dim type would then just give ftbsbc:stoneblock and no the specific dim

I am also having this issue, the only solution was to allow other "teams" to use my main (first) dimension to create their machines. This issue happened when someone else on the server noticed their wither builder only placing soul sand. It refused to place the skulls. Made no sense. Then randomly I discovered my base had floating wither skulls. Putting that together its spawning some blocks in my base. As on his it is not placing the blocks. Very odd, this is.

Also to add it duplicated the skulls. The one dimension it did not consume/place the skulls. However, there are skulls in my base. This could be exploited using a block placer with the same effect.

It can just fixed by using Object.hashcode() instead, I has made a PR for this:
#1332