I'm playing Hetepsenusret. I've been playing for quite some time and have a population >10000 spread over all three land masses. I just recently expanded to the eastern land mass, but already have two housing blocks over there. This was functioning very well and I was beginning to advance one of those housing blocks past the beer stage, which is where I limit the majority of my housing when I can't make my own barley.
When I provide my houses with a functioning scribal school, those with room advance to common residences, while those without remain spacious apartments. At this point, I regularly destroy some of the spacious apartments to allow apartments to grow into 2x2 buildings.
This time, when I do that, my other housing block immediately reports being cut off from the rest of the kingdom. This has happened twice after reloads. I have checked to make sure I didn't delete roads, and have even drawn new roads on the map to try to reconnect. I have also ensured that my ferry crossings are fully staffed. Any ideas or workarounds would be appreciated.