I cannot copy the text style in Microsoft Word using the keyboard shortcut

For years I have used Cmd+Shift+C to copy text style in Microsoft Word, and then Cmd+Shift+V to paste the style. Recently when I'm in Word (or Excel) and type Cmd+Shift+C it always opens my Calendar program (which happens to be BusyCal, though I don't think that's pertinent to this issue). I can copy the style by clicking on the format paintbrush, and then paste the style using Cmd+Shift+V. But can't copy using Cmd+Shift+C. I've checked "Customize Keyboard" in MS Word and it shows Cmd+Shift+C as the shortcut to copy the style. I've checked **System Preferences** > **Keyboard** > **Shortcuts**, no issue there. I've checked Keyboard Maestro, which I use for lots of shortcuts, and nothing is defined in there for Cmd+Shift+C. I don't know what else to try. Restarting my Mac seemed to fix the problem for at least one copy and paste of a style, but then it goes back to opening my calendar (and often creating an event with the text I had copied!). The issue occurs in Word & Excel, but not in PowerPoint. Help! I use the Cmd+Shift+C keyboard shortcut a hundred times a day!