Does astigmatism change like this?

The requirements for the best vision change as the cataracts advance . You show a typical change happening in your vision under the circumstances. Your astigmatism correction is simply another correction for myopia but in a single meridian. It can change as much as the spherical myopia correction. It all looks normal.

Cataracts are a decrease in clarity of the lens of your eye. As the lens becomes less transparent, it also changes in shape. These changes are expected to cause an increase in myopia and against the rule astigmatism or a decrease in with the rule astigmatism. When the prescription is written in plus cylinder form, against the rule is astigmatism with an axis close to 180. You have that change. Less expected is your decrease in myopia. things don't always go as expected.

Aw man! I remember having to fight Astigmatism in A Link to the Past! Man, those were some good times.

You fail to say hold old you are, but yes, your eyes change as you age and the lenses harden and so gradually lose their "power of accommodation" which is why I need reading glasses routinely at the age of 52 and only needed them very occasionally when I was 42.

It's also fairly normal to find that short-sighted people may become less short-sighted, and your results show that's precisely what appears to be happening.

But if you want specific answers relating to your individual eyes then instead of asking a world of total strangers who have no access to wider aspects of your health then ask your optician. It's what he or she is trained to do and is precisely why when you first register with one you're normally asked health questions which may appear to have zilch to do with your eyes, and why it's now good practise to update that information before every eye test or at least annually.