Project Browser - new sections in a xref shouldn't be seen here?

Hi All,
I'm preparing a BIM Advanced training for a client, using the Main project (Advanced course), that includes MainBuilding and SecondBuilding as xrefs.
1. Project Browser is ok with all BIM sections and sheets of MainBuilding.
2. I open SecondBuilding and apply BIMIFY to create all sections (Floor and Elevations) there, and save it.
3. In Main I reload SecondBuilding and section entities are displayed there.
4. Going to Project Browser, Update, Section tab doesn't include the new sections.

Am I missing something?
Thanks in advance