Bletchley Park Lv 1
While trimming one of the four structures allows one to resolve local clash issues and idealizations, untrimming it will introduce new clashes in other copies of the structure that are out of reach from the previously clashing sidechains in the original copy. One explanation might be an unintended parameteral link between the copies.
It is still possible to resolve the newly introduced clashes in the other copy, but it takes extra effort and time to do so. It is unclear if these unintentional potential links may influence other behaviour down the processing pipeline.
(No upload made as the behaviour should be obvious when trying this puzzle yourself).
Algorithmicly:
A has clash, B has clash, trim A, fix A, untrim fixed A, trim B, fix B, untrim fixed B, A now has a new clash.
