What happens if you double-click "SanDisk SD Card" in one of the file displays on the right?
MTP is fairly unreliable in general (in both Opus and Explorer), so the suggestions here may help with your phone:
What happens if you double-click "SanDisk SD Card" in one of the file displays on the right?
MTP is fairly unreliable in general (in both Opus and Explorer), so the suggestions here may help with your phone: