mm2023

Hi all, Hope somebody can help. I'm in need of some assistance to resolve an error I've discovered on my XT3. (I've been filming for around 2 years with this camera). When I turned on my camera, on-screen and also exported footage, coloured blobs are in the corners. After checking both the lens and sensor, I can't see any scratches or damage. Any ideas on what could be causing this? Every time I turn on the camera, these coloured blobs keep appearing. Thanks, Matt