All date/time tracked by BAM must be expressed in UTC. BAM depends on this to provide accurate durations, among many other things. This is clearly explained here . It was also the case for BizTalk 2004 even if the documentation gave subtle hints instead...

When using the BAM Portal Activity Search feature, you may be directed to an error page with the above error message. This error message means that there are instances with duplicate ID in the activity you were searching. If you look at the "Application...