Transparent backgrounds are no longer allowed

Using SAB 8.3, I have a new project for which I have followed the instructions and added a foreground and background image for an adaptive icon.
But, I get this warning on google play:
“Google Play will dynamically add rounded corners and drop shadows to your icon. Transparent backgrounds are no longer allowed”
Should I proceed as is, or ignore the transparency request in SAB and put something else in?
Or is it complaining about the older legacy icons (i.e. should I only include the new, and not both)?
Appreciate your guidance.