System information (version)

• OpenCV => 4.5.5
• Operating System / Platform => Ubuntu 20.04
• Compiler => g++

Detailed description

Usually in opencv, the conversion from BGRA to BGR via IMREAD_COLOR or cvtColor set the transparent background as black.
However, for this image it seem to generate an inconsistant background.

Steps to reproduce

import cv2

img = cv2.imread(path, cv2.IMREAD_COLOR)
cv2.imshow('window', img)
cv2.waitKey(0)

Original image:
Output image:

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues,
  forum.opencv.org, Stack Overflow, etc and have not found any solution
• I updated to the latest OpenCV version and the issue is still there
• There is reproducer code and related data files: videos, images, onnx, etc