Glo Shelve that cannot bo removed

I just initialized my son's new glow.

We have already several touch/glow in the family, so the other devices have already been sunc'ed with kobo desktop

So, after first sync on kobo desktop, and update to 2.3.1, the new glow ended up with 5 pages of empty shelves that I had to remove manually. That in itself is a real pain.

But 2 shelves were present with the same name, and no matter what I try, I cannot remove them. I have tried renaming one, but that does not work either.

It's really stupid to create on one devices shelves that were present on another one. Each device should have its own shelve list.

I only have side loaded epubs on the other devices.

Any hint for :
1) Removing those 2 empty shelves
2) Preventing shelves from 1 device from being created to another device every time I sync on of our readers.

Would be welcome.