Not sure if this is a bug and hoping others can test it out.
Open a blank document. Add a layout. Add a rectangle (any size). Right-click the rectangle > Properties. Placement. Update some of the placement values. While the cursor is still in the value box, click over to Symbol.
When I do this, ArcGIS Pro crashes. I'm not sure if it has to do with the new value not registering before trying to bring up the Symbol menu. You'll notice though that the rectangle never updates the final value change before the program crashes.