"Missing" handler events (that aren't missing)

Okay, this is really weird.

I have it setup so that I get an email each time an error occurs on
this site I just launched a couple weeks ago. It's in Coldbox 2.6.4
on CF9.0.1. I've seen three of these errors now, from last night:

An invalid event has been detected: [handlers.main] The action
requested: [index] does not exists in the specified handler.

Two were like the one above, the third was for a different "missing"
event, but these do very much exist in the main.cfc handler.

Has anybody ever seen this sort of thing happen? I just did a reinit
of the framework in case that helps.