blue rubber strap turning black, as his appeared to be
well, i have no idea what's causing it, but mine has darkened so much, it is turning black

hasn't been out of the house a dozen times, gets worn about once every two weeks, otherwise it's on a bullino winder with an acrylic cover sealing it from dust, atmospheric contaminants

have no idea what's going on but it is definitely not the blue it was before

... You say the watch was out of the house only rarely. This would take my usual suspect, ultra-violet radiation, from the list. Other possibilities could be high humidity level compromising the saturation of the colour pigments in the rubber, maybe chemical vapours in the winder box (plastic softeners?)? All I can suggest is to contact UN, if they have thoughts or informations.

Best regards,
Marcus

but had ruled those out as it's seen so little time off the watchwinder, relative to wear time

but you might have something there on the plastic in the winder
it was a new winder, and not only is the cup plastic (more a flexible polymer, similiar to car dashboard plastic) and there's an outer cup surrounding the whole cup

i know car plastic gives off a pretty toxic vapors when new, but thought that was in hot sun and the heat of the car helping it release those vapours

could be, don't know
as the rubber is already showing use, i'm going to remove the rubber and see what a good scrubbing will do and if it cleans it up, seal it with some pure silicone