What does the back of the ptx3 look like? I had an issue with a couple of tpmc-3x docks where the circular "pin" needed to be adjusted If the horizontal dock has this same pin you may be able to resolve the issue.

See where the remote attaches to the dock? The bottom/right portion has the circular pin that i adjusted. I took the dock apart and pushed it out releasing it from the hot glue. I pushed it out so that the pin was more exposed and put some new hotglue in. Done.