Speculation is very normal when minimal information is provided
Particularly when it's the future queen, she's in for longer than you might expect, it's happened suddenly, engagements for at least 3 months are being cancelled, and her husband's engagements have (I think?) also been cancelled.
It's not a run of the mill happening.
Then you've got the King announcing upcoming prostate surgery on the same day.
I think his surgery was very much planned and an announcement made ready, and I think hers seems like it was one or two steps down from an emergency, hence an announcement afterwards.