I had noticed a change in font and increase in text size when the update occurred. Eventually concluded that aesthetics apart, it was actually more legible for me with aging eyes and old screen...
But I have since experienced sudden changes in size. A couple of times now.
This morning I typed a post as normal. When I submitted it everything went to "small print" size.
I looked through the control panel to see if there were any controls available and it suddenly went back to big

And while I'm mentioning stuff - the facility to drag and drop a few words when editing ones efforts before going public doesn't seem to work any more. I can highlight them, and drag them, but when I take my finger off they just go to the end of the last line typed