As per KB BB732380, in RE7.92, "When checking for duplicates from a constituent record by going to Constituent > Duplicate Search, there is no option to merge from this screen. This feature, that was removed in this "update", allowed quick constituent merges. Now, we have to write down the ID, and go to the Merge feature in the same menu. Not sure how a revised algorithm affects a button that calls the merge funciton, and pre-populates the Merge From and the Merge To fields - especially since the new algorithm still gives us a list of possible matches, only with more information available.