How to tune a unison on a piano<br>Open up the piano to expose both the tuning pins and the keys. Depending on the piano, this usually requires removal of the front part of the upper cabinet and sometimes the key cover. Play the offending note and find the strings associated with that note.

Based on the paragraph above can we conclude that "Offending notes cannot be caused by improperly tuned pianos."?
It's impossible to say