Looks like two things, though impossible to say for sure without knowing more about the scene (also let us know, which host software, which version of Corona, as well as a description of how the scene is set up). Anyway, my guess is:
1) You have a light source very close to the wall, causing a super bright area
2) You have AI denoising enabled, which is causing the strange patterning in the bright spot, which may be why you don't recognize it as a bright highlight from a light (leave it to run for more passes and it will resolve, or turn off AI denoising)
Due to the AI denoising (or what I think is AI denoising), I can't really tell if there might be something else going on in there.