Hi Robert @VisualConduct
you need to flatten these two. In the end, the larger definition you post can be simplified, and this would be what you could have asked to get an answer more quickly: why do the datatree below gets subtracted from different meshes?
The answer is that a tree is a list of lists. Because this component Boolean-subtracts a list of meshes from a list of meshes, a tree (here two lists in B) requires also two input lists in A. Because there is only one list with one item, A gets used twice for each of the lists in B.
BooleanTest_02.gh (348.2 KB)