Shortcut disabled, but it's not

I'm suddenly getting popup warnings about macros being disabled, and the macros don't work. But they're not disabled!? They were all working fine, now any attempt to trigger even simple macros fails with the disabled message. To be clear, neither the group nor the individual macros, or the steps within, are disabled. What am I missing?

And just as mysteriously as it stopped working – it started again! I guess the question becomes - what was that all about! Has anyone else seen anything like this? What did I do to cause, and then may undo this behaviour?