I have an Archer rubber strap in Orange on my baby Dreadnought which I usually only wear occasionally, but I wore it constantly whilst at Le Mans for 6 days so it didn't get lost.

Yesterday I noticed what both I and Mrs B think looks very much like a burn which exactly corresponds to the positioning of the strap - neither the watch back or the buckle location have the same redness/minor blistering.

Has anyone heard or such a thing being caused by whatever rubber these are made of?