The problem exists since Origin 2020b.

To reproduce

1. New a wks and add one more column. Fill all columns with random numbers.

2. Highlight the whole wks and make a bubble plot.

3. Open PD and go to Symbol tab. The Transparency is 50%. Change Symbol shape to solid circle and click OK.
   ==> transparence fail to work.
   Note:

4. no problem if uncheck Transparency for Fill Only, before change symbol shape.