Siri Activates by “PC”

When I have “Listen for Hey Siri” and “Press Home for Siri” turned on, if I say “PC” just in conversation (without Hey Siri) Siri activates and says it can’t find computer keyboard suppliers. If I press and hold the home button and say “PC” the same thing happens. This seems very strange. Does anyone else have this problem?

iOS 11.2.1, iPad Pro 10.5