The moon phases have been wrong since A3 came out as well as the Days/Dates being incorrect.
As an example: Jan 10, 2020 is a full moon, ARMA says it is not and the next full moon will be on the 26th. the only time ARMA reports a full moon.
See: Moon Cycles
Also I noted just the other day that the days/dates are really off.
Example: Today is Friday Jan. 17th, 2020 - The '3rd' Friday of the month.
ARMA On Day 17 = Saturday
ARMA on the 3rd Friday = Day 16
This fails always - mods or no mods.
I have tried this with the 'default' ARAM (i.e., no mods) and it still does this.
I have not checked other years, but 2020 is all screwed up and the moon phases have bee wrong for 2018, 2019, and now 2020.
Thanks for looking and correcting it!