ZS20 intelligent burst
While I was at the Butterfly Pavilion, I did use a burst that didn't have a set number. Unfortunately, I don't remember what I did (3rd time using the camera), but when taking one picture in P mode, there were 29 total of a burst set and they were all in focus. I was switching around trying to catch whatever I could.
On another occasions, I also used the 10 burst -- some were not in focus, some were not; the 2-5 burst worked fine for me and all were in focus.