The functionality of the script command setDriveOnPath has changed from prior functionality. Prior to the current state, units driving on a path via setDriveOnPath would ignore contact with enemy units for the purposes of navigation, but the gunners would still engage targets appropriately.

Between 2018-03-10 and 2018-04-29 this was changed to the current functionality, whereby units drive on the path until they make contact, whereby normal combat AI takes over and the path is functionally discarded. Unfortunately I do not have an exact build as to when this change was first observed.