IMHO what happens is that Webex on your Phone thinks it's a picture taken with the front-facing camera and, not seeing any exifs, mirrors it by default. So the problem is really with Webex (on your phone) and not with Gimp (my own Webex persona is also an output from Gimp and displays OK, but I use Webex on a PC).
Instead of removing the EXIF data, try using exiftool to force normal orientation:
Instead of removing the EXIF data, try using exiftool to force normal orientation:
Code:
exiftool -n -Orientation=1 <img>
# or
exiftool -Orientation=top,left <img>