I have a smartlist that finds only 2 people in a picture. I had to use this rule to exclude pics where these 2 people were 2 of several in a picture. This way I can have pics with ONLY my 2 daughters in them. MC 13 will properly create the smartlist, but then breaks it if I go back in to edit.
Here's an example: I use the rule [=isequal([people],sue;bob,1)]=1 or [=isequal([people],bob;sue,1)]=1 to find pics with sue and bob, or bob and sue. If I go back in to edit this smartlist rule, the rule is now split into 2 custom rules instead of one. The 2 rules represent either side of the 'or' in the formula. So I get [=isequal([people],sue;bob,1)]=1 for one rule and [=isequal([people],bob;sue,1)]=1 for the second. When I choose OK, the result is empty. I can delete one rule, cut and paste the rule back into 1 rule and add the 'or' and it will work again, at least until I go and edit it again.