How you handle this depends on what you want to do. If you have completed all the nodes with in the city limits and it is just the nodes due to the “town line bug” as I call it, some people choose to utilize the “manually complete” button. The next time OSM updates for the area your manual complete will not be needed anymore. Others are waiting and just leaving things as partially complete, knowing they will become complete when the time comes.
I personally have 5 smaller cities/towns in my area that will switch to 100% when the next update takes place.