Some87

I got my car one moth ago and only the rear bumper right behind the tire had cracked paint on it. Now the front bumper right under the headlight and right over the exhaust (single exhaust) started cracking. It's kind of strange too because the all the cracks are horizontal straight lines. The paint looks oem and matches the door jambs. The last owner said the car has been garage kept its whole life btw it's a MY02. The only thing that has changed is that I live in an apartment so it now sits outside in the sun which it gets over 105° F here in the summer. Could it be that the bumpers were resprayed? I know almost nothing about paint at all so just figured I would ask. If it would help I could get a picture.