Hello,
It's not duplicates. ALV and AL4 use the same presets. You normally can't remove the banks from ALV without removing them from AL4 too.
However - It's strange the presets is gone from ALV but not from AL4.
Are the factory presets also gone from ALV?
Have you installed both AL4 and ALV with Arturia Software Center (ASC), so all the install path's are the same, and there is'nt any install mess?
Perhaps try to reinstall ALV.
If all this is in order, then perhaps it can be a strange preset database issue, that can be solved by rebuilding the database. But i would think that to be very strange if AL4 work.