My collection structure had been working fine for a couple of weeks, then the same issue as always.
I decide to try my luck and contacted Kobo Support on twitter. They answered quickly and after a couple of questions more (and repeating the issue a couple of times :P ), they escalated the issue to the technical team. I don't know if they will manage to solve the issue, but they have been quite welcoming so far, so if you are still struggling with this issue, it's worth a shot
