Keyboard shortcut for service only works after I manually run the service
Found the answer in this Apple Support Community thread:


Bug: Keyboard shortcut keys do not always activate a service (a workflow)


Keyboard shortcuts for services will only work properly if they have a ⌘ command key in them.  That is, cmd-ctrl-k works, but ctrl-k needs help.  The "help" is to go to the app's menu bar and hover over the services so it sees them. That works until you quit the app.

But, if the shortcut contains the ⌘ command key, it works as expected.