Portal edit does not update

Hi everyone!
I created a portal page on a PDC and chose it to be avialable also on the BDC and on a Slave. On the first save the portal was replicated on the BDC and the Slave. Later, I edited the portal by splitting the entries into two rows. However, this change is only visible on the portal page of the PDC, the other two do not get the changes. I built a forward lookup zone portal.domain.tld - this way one of the three responds - but only if the one responding is the PDC I get the “right” portal page. Can someone help me fix this?

could anyone at least give me some tips where to search?