Not sure if this is the same issue, but I get implausible points when I go into a shop or other building. This messes up the trace. I don’t know if citystrides.com import the timestamp for each lat/long point, but if so it would be pretty easy to identify suspect points as the speed will be implausible. Stepping through the trace in sequence and deleting implausible points ‘should’ be reasonably easy. I’ve done this in the past for vehicle data loggers and it works nicely.