Rod -- I'm not seeing the issue either. When I search for a message ID (your example showed the message ID) and use Related Traffic, I only get results for that message ID in the results. This is running a more recent build than you, but we haven't touched that area.
Sebastien, I do see the issue you're referencing in the last 16.x build. However, I'm not sure we'll get a fix out unless there's another public release of 16.x. That's TBD at this point.
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