I could not play my private island anymore due to a ping of greater than 300ms - i found the root cause in the cinematic sequence device / Level sequence. As soon as i stopped the playback, the ping went back to normal. I could not fix this problem, even by reducing to a very simple transform /position update and changing to a very simple object that was modified. It seems just broken. I am taking part in the summer callout and the moving object was an essential requirement - i am now going to remove it, hoping for indulgence.
Thanks for your help!