When converting a project from 4.10/4.11 to 4.12(or later) the relative scale of the sockets on skeletal meshes will be changed to 1,1,1 regardless of the previous settings.
---- Alternative Repro Steps ----
The relative scale of the sockets have changed to 1,1,1 (this can easily be seen with the preview meshes)
The relative scale remains the same
Head over to the existingAnswerHub thread and let us know what's up.