Sync between two Kobos

Hi everyone,

I have a question for the Kobo savvy amongst you.

Now that I have two Kobo ereaders, I was expecting to make use of the sync (between devices) feature. So the other day, I started reading a book bought at Kobo store (original kepub) on the Aura. Before leaving for work, I synchronized the Aura then the Mini and the book opened on the very same page I left it :eek: Note that I was somewhere in a chapter and that the screen sizes plus different fonts make it for much more "screen pages" on the Mini than on the Aura (something like 2,5 times more).
After that, I synchronized the Mini, then the Aura expecting to resume my reading on the latter. But it didn't work. And it haven't worked after either. Say I'm 33% through on the Mini and 25% through on the Aura. When synchronizing the Mini and after that the Aura, the percentages will remain 25% on the Aura.

Is there something else to do to update the reading progress? I am using different fonts on the two devices, can this be the reason?

Books on both ereaders are original kepub ones and I am logged into the same account on both devices.

Any suggestion is welcomed :)