Replicated in Inkscape 0.48.5 r10040 on Windows 10 but no longer an issue in 0.92.3 ppa Linux Mint 19.1 (also in 1.0 release (4035a4fb49) Windows 10). Now on copy and paste if a duplicate marker is created, it is referenced
Issues currently exist for extra markers being created in https://gitlab.com/inkscape/inbox/-/issues/2850 https://gitlab.com/inkscape/inbox/-/issues/2751 so safe to close
Replicated in Inkscape 0.48.5 r10040 on Windows 10 but no longer an issue in 0.92.3 ppa Linux Mint 19.1 (also in 1.0 release (4035a4fb49) Windows 10). Now on copy and paste if a duplicate marker is created, it is referenced
Issues currently exist for extra markers being created in https:/ /gitlab. com/inkscape/ inbox/- /issues/ 2850 https:/ /gitlab. com/inkscape/ inbox/- /issues/ 2751 so safe to close