To add to the original post:
It appears that the Direct monitoring mode has (as one would expect) an impact on when the routing is adjusted. I’ve changed the mode to “Manual” which isn’t really what I want, but at least now once I establish the routing (by selecting DM on the audio track, and then clicking on a Source Mix button on CR) it remains routed between takes (though I don’t hear any audio that’s already on the track).