Good afternoon! Faced such a problem. I use the "transform constraint" function. I increase the dependence of the "translate" parameter. In Spain, everything looks right. Exporting to json for GameMaker, with a runtime version that supports Spine 4.0. As a result, I get the inheritance of coordinates only along the X axis. The bone, which should inherit the coordinates of the target bone, moves only horizontally. At the same time, entries are visible in the json that are associated with the inheritance of X coordinates, but there are no entries about the inheritance of Y coordinates.
