upgrade of port fails because of existing link

[Torfinn Ingolfsen]

Often, a port fails to upgrade because of an existing link. Example:
====> Compressing man pages (compress-man)
===>   Installing ldconfig configuration file
--->  Backing up the old version
--->  Uninstalling the old version
[Reading data from pkg(8) ... - 990 packages found - done]
--->  Deinstalling 'qt5-dbus-5.12.1'
--->  Preserving /usr/local/lib/qt5/libQt5DBus.so.5 as
/usr/local/lib/compat/pkg/libQt5DBus.so.5
cp: symlink: libQt5DBus.so.5.12.1: File exists
Copy failed!
[Reading data from pkg(8) ... - 990 packages found - done]
** Listing the failed packages (-:ignored / *:skipped / !:failed)
    ! qt5-dbus-5.12.1    (copy failed)

Shouldn't the ports system work better than this?
(yes, I can manually remove the offending link and re-run the upgrade,
but it is a nuisance)
-- 
Regards,
Torfinn Ingolfsen