Replying to Car experts halp me

so i just recently bought a 06 civic si. according to carfax and multiple mechanics, its history is free of any accidents and everything seems clean. today i just noticed that the rear right seam of the bumper is not flush with the side panel. google found no answers for me, but is there any particular reason this would have happened with nobody making contact with my car? does this happen with extended periods of cold weather? clueless. appreciate any input before i take it to a body shop