Agreed @jesse, I believe the issue here is related to the subpath. @TommyA, for security reasons, the decision was made between 4.2 and 4.3, with refinements in subsequent versions, to be stricter when handling links in the Desktop app. Part of this includes determining whether a link is internal to MM or external. Internal links are just loaded in the main window to allow regular navigation in MM to occur, while the decision was made to pretty much open all other links in the OS’s default application for a given link (usually a browser). I suspect your scenario is falling between the cracks.
Appreciate the feedback! We will create a ticket to investigate this scenario on our end, stay tuned!