Don't worry about it. I know how busy you are, and I really have no idea how you keep up with all that you do :) I only moderate a community plus few other minor things and RL, and barely finding enough time to write and post once a week and/or read and keep up with things.

About the energy conservation:
It "can", but with current theories, Noether's theorem, and data, it "is" violated on that timescale due to no translation invariance in an expanding universe as you have mentioned.

Regarding CMB energy loss;
As far as I know, there isn't as nearly CMB to cover for it. Dark energy is increasing at a much higher rate than the CMB loses energy.

Ofcourse, we are not throwing out conservation of energy or the second law of thermodynamics (which is another topic), as violations are only on such extremes and it is unhelpful to do so.

Thanks for the always insightful comments, and wish you a wonderful week too!