Sure thing, I will do that!
A few things I also tried:
1. I disabled/deleted almost all other system/app shortcuts and touchpad gesture, still not working.
2. While testing it, I notice that maybe something else was triggered at the same time. For example, the Developer tools of Chrome was triggered. And this behavior is the same no matter which hotkey I chose for the workflow, so I suspect it is not due to a hotkey-conflict issue. I also tried the define the same hotkey in iTerm2 to test possible hotkey-conflict, the hotkey recognized by iTerm2 was immediately cleared and set to ⌘C. Again, it doesn't matter which hotkey I choose for the workflow, it seems like ⌘C was recognized as long as I type this hotkey in iTerm2.
3. If I chose a different Argument option in my workflow, either text, or macOS Clipboard Contents, the workflow would work and no extra stuff (i.e. developer tool of chrome) was triggered.
At the very beginning, I installed Alfred 1 from the app store, then uninstall and get the Alfred 3 after realizing it was outdated. Not sure if this can cause anything...