We have configured a trace data collector from a script generated by profiler
We have been seeing duplicate entries in snapshots.trace_data each with its own snapshot_id.
After checking the SSIS package SqlTraceUpload.dtsx and performing a profiler trace on the MDW database we noitced 2 calls were made to snapshots.sp_trace_update_info for each trace collector configured, per iteration . On the second call when there was an event count of 0 we also saw the last_event_sequence was 0. This figure was written to [snapshots].[trace_info]