I researched the advanced sewage function in the neighbouring city already (note: they are in the same region!), but this city wanted me to research it again. However, other cities in the same region can run the advanced sewage function seamlessly.
It is a bit sad as I note the similar situation happened in another neighbouring city in the same region - this time it was the advanced garbage disposal. I researched it in the first city in the same region, but that research result was not automatically transferred. I have been playing this game for more than 1000 hours. I really hope this issue could be resolved immediatedly.
