Thank you for the link! About the twofold nature of (at least?) Aries and Taurus, I can only come up with two possible explanations: either a) These months are related to some magical festivals, special dates etc. that cause the month to be divided into a "day" and a "night" part; or b) These months are related to the moon diagram on page f67r2, and a leap month/leap days denoted by red moons can only occur on these months...
The figure next to the moon diagram on p. f67r1 could easily be related to a lunar calendar with a 30 day month: 12+9+9=30; i.e. the single stars would be counted only once.
Of course, then also the moon diagram could be read in cycles so that leap months would only come in certain years... I believe that the colouring is original work by the VMs author and he did not make a mistake in colouring - had he made a mistake he could have used additional colours to make his intentions clear, but he chose to leave the page as it is.