Hey Neehal, I’ve checked this with the support team and got the following response:

Your drop down is dropping behind the frame below, so you’ll need to make sure that the frame order in the layers panel reflects the order of the frames in canvas going top to bottom. In the case that you’ve nested your dropdown frames inside an auto layout frame, you’ll want to set the canvas stacking property of your auto layout frame to “first on top”.

Hope this helps!