This has been confirmed.
Steps for devs to re-produce:
1. Browse to Rig Builder :
2. Create or Edit a Rig. When creating or editing, browse to the bottom of the page to ''Main Image''. Upload an image and save your rig.
3. Once taken back to your rig, you will notice a small image avatar of the image you uploaded to the left of the screen, click on it and it will reveal your image.
4. Edit your rig and replace that image with a new one and save your rig.
5. When you are back at your rig, you will notice that your avatar image is now changed, however when you click to reveal, it shows up the image you had just replaced.