clicking on app icon in the dock brings me to the wrong app

Please read the following user tip and restate your question/problem in detail: 

     Writing an Effective Apple Support Communities Question - Apple Community

Have you tried removing the apps from the Dock and adding them back from the Applications folder?

Try a restart. If no joy there, try a safe mode start: Start up your Mac in safe mode - Apple Support

Which app by name are you clicking and which app by name is opening? For example: you click Mail but Calendar opens.