Well I checked out the scene in Etude on the 90minute Canadian version and it is just as I had posted earlier....JC must have just screwed up the line!!
In the Canadian one Columbo says.."I'm a fan of yours...a really big fan...." and Alex says..."Are you interested in piano concertos?"
And on the 2 hour version and the 90minute one Columbo says about the typewriter..."Why would a woman who's going to commit suicide type a goodbye note...put it in the machine and take it out again." That is obviously a flubbed line also...he should have said the reverse. Obviously the 2 friends were doing a little partying on the set!!!