🐞 Periodical seasons shift disregarding leap months

[NormBleac]

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Expected Behavior

In my calendar I have defined 12 months of lengths alternating between 29 and 30 days, and added five leap months within a 13 year cycle, so that on average my calendar should sync up with a year of 365.24 days. I set seasons to 'periodic', with a length of 91.38461538 because (strangely) this is what the interface suggests is the right value for even distribution.
So what I expected was a slight seasonal drift over a span of years.

Current behaviour

The resulting drift was a constant approx. 11 day shift forward per year, so that each season started about 11 days later in the year, each year. Most curiously, this shift was unaffected by the occurrence of my leap months (which did appear at the right interval by the way). As far as I could see, each occurring leap month was simply marked as an additional 29 or 30 days of the current season, which would result in some seasons lasting 120 days rather than the planned 91.

Reproduction

1. Create a new Calendar
2. Add 12 months with lengths alternating between 29 and 30
3. Add 5 intercalary months with length 29, interval 13, and offsets 1,4,7,10,13 respectively
4. Add 4 seasons, and set seasonal length to 'periodic' and press 'evenly distributed'
5. Check the resulting calendar and witness the seasons drifting far more than expected as you progress the years

Which Operating Systems are you using?

• Android
• iPhone/iPad
• Linux
• macOS
• Windows

Obsidian Version Check

1.6.7 and 1.5.3

Plugin Version

2.0.0

Confirmation

• I have disabled all other plugins and the issue still persists.

Possible solution

It seems to me that Calendarium is completely disregarding my leap months when matching seasons to days and as a result ends up with a year that is 11 days short (exactly the amount of days that my leap months would add, on average, over the course of 13 years) so the solution would have to lie in a remedy of this disregard.