After killing the ended dragon, me (using the Windows 10 version) and my brother (using the Nintendo switch version) both went through the gateway portal to find end cities and it worked as expected. After we both died while there, we attempted to go back but now every time we throw a pearl or use water to get into the gateway portal we are instead taken to the middle of main island instead of to the outside islands. We have tried about 10 times with the same result.