How to prevent the "-1" suffix in network drive paths?
I have seen this happen when there is already a volume with the given name and the OS needs to create a new name to mount the volume as you can't have a duplicate name -- thus the suffix.

The first thing to do is, make sure that you don't have any other volumes with the same name. If you do, perhaps you can rename one or only use one at a time.

I've also seen some applications that use a path for an external volume will create a folder under /Volumes/ if the volume has been disconnected and the path doesn't exist. This causes the suffix the next time the volume is reconnected. To fix this you will need to disconnect the volume, remove the extraneous folder, and then reconnect the volume. It should mount without the suffix.