Copy-paste errors are much more common than those once in a lifetime bugs nobody care about. Or are you telling me you never ever made a copy-paste error after your first week of programming?
They are one of the most pernicious error to find because the person reading is doing the exact same mistake as the writer, seeing the first instance is correct, they assume the rest is too.
This is what I love about PVS studio, it actually catches real life bugs like this one. They may look simple when shown in the spotlight but they do happen and can easily go unavoided. Instead of most other analyzers(or maybe I should call them linters) that only complain when you do something that obviously depends on UB like casting a pointer to an int, or missing paranthesis vs operator precedence.
Copy-paste errors are easier to detect if the code is lined up properly. The first example would have been fairly obvious if each if-then statement were put on one line instead of two, and then all the clauses would line up. The error would then have stood out.
They are one of the most pernicious error to find because the person reading is doing the exact same mistake as the writer, seeing the first instance is correct, they assume the rest is too.