Based on the timestamps, it looks like this person created their profile while the bot was actually running. To avoid having to check each learner against the database, the bot just finds new category members since the last time it started running. If someone makes their profile in the short time between the time the bot starts running and the time it checks their category, the bot will match them twice.
By my quick calculations, this should happen perhaps one time in 50. Is this worth adding in the database check, @I_JethroBT? It will be slower and also another potential point of failure, but it would solve this problem.
@Fhocutt I think we can do without it then, given that it will happen infrequently-- and indeed, out of the 60 or so profiles in the space so far, this is the only case I've seen this double matching happen. I'll inform mentors that will happen rarely, but that whoever gets matched first is the *actual* mentor.