This behavior was duplicated with the Tekton MM (multiple master) font dated 1995-03-01. A newer version of Tekton MM, dated 1996-04-16, does not exhibit these behaviors. This font was distributed in the Adobe Deluxe 30 Fonts set with ATM Deluxe, and was perhaps available in other packages as well.
Customers who are experiencing the issues described in this article should update to the newer version of the font.