Before 70,000 AD, was the moon cycle only 26 days?

[Fomer808]

Hi!
Recently, I discovered two phenomena when using software Stellarium to watch the moon.
①Starting from 60,000 BC and going forward, each month only has 28 days. Then starting from 70,000 BC and going forward, each month only has 26 days.
②The moon begins to have very obvious changes in distance and distance.
So, I'm wondering if this is a software problem or is this what real astronomical calculations are?
Thanks !

[gzotti]

I have written Appendix F of the User Guide for you.

[Fomer808]

OK, thank you very much!