Dock Icons Missing in Mojave

After upgrading to Mojave, several of my dock icons were missing--the default icon was displayed instead. A similar problem had been reported with previous OS upgrades. A recommended solution was restarting in safe mode, then restarting again in normal mode. After I did this, on my dual monitor display, the dock on the right shows the correct icons, while the one on the left does not. Apps affected are iTunes, Keynote, FaceTime, and Photos. The icons are not correct in the Applications folder, either. Any suggestions?