Calenders with moons don't correctly show the waning phases, rather just reusing the waxing phases. You can see how the light part of the symbol moves from right to left, but the shadow then moves in revers; left to right. This means that there is never a time when the left side of the moon is illuminated unless the right is also illuminated! For example, the half-moon before and after a new moon look identical, when they should actually be opposites!
The problem:
Create a calendar, add a moon with phases long enough to show a waning phase (29.53 is a good approximation of earth's moon).
Note that I use Microsoft Edge, but I have also tested it on Google Chrome and gotten identical results.
Ugh, of course the images uploaded backwards.
Hey, thanks for reporting! We are currently working on the next version of Calendar which will resolve this issue, please keep an eye out for an update soon.