If you do 2 events and you finish the second event before the first event’s fit file has been processed then the processing of the second event will break.
Example: You do a race that is 30:00 long, then do another race or group ride that is 1 hour long. If you finish the second event before the bolt has turned blue on the first, then the processing of the second event will break. And the way it breaks is it takes the length of the first event and processes that much of the second event (i.e. the first 30 minutes of it in this example).
This bug has been around for about a year I think but I’ve only just worked out exactly what is going on.
I can give you specific examples if you like but hopefully the explanation is enough.