This has mostly been tested with Project Red blocks and CBMicroblock blocks, but other mods might have similar conflicts. From what we understand, any set of blocks attached to a gantry contraption should move along with them, and this is true for most blocks. However, some specific blocks (e.g. Project Red wiring, covers) do not have this functionality.

A demo video can be seen here. Essentially, while normal blocks can automatically be carried along with the contraption, special blocks such as wires are treated as if they weren't part of the contraption. The gantry still functions correctly if it is unblocked in the other direction, resorting to virtually deleting the incompatible blocks until the gantry can re-dock. This creates a "pulling" effect, but preventing a "push".

This can be circumvented by a very glitchy maneuver; pulsing the gantry in the direction it can pull in, rendering the incompatible blocks invisible first, then resuming the proper direction will allow the contraption to be "pushed". That can be seen here. This is, however, very glitchy, and in some odd cases can result in an infinite loop of the gantry docking, realizing it isn't in a valid configuration, undocking, and repeat. Due to what I believe is error-checking code, the gantry luckily realizes this and breaks a part of the system to prevent the game from being overloaded.

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