The height of the frame is 400, and the height of the exported PNG image is 401, which is not equal to the height of the frame.
Hey @LatteGuy, thanks for flagging this!
Can you please confirm that your frame is sitting on whole pixels before attempting to export the frame, and let us know if that makes a difference?
If the exported png is still the wrong size, are you able to share your file with us?
If so, please include a link to the file, and share edit access with support-share@figma.com.