Another 5127G here, fitted with a glossy black PP strap marked "Cousu main" which, 'babelfish' tells me, translates as 'bent hand'. Bent by hand? Hand shaped? Who knows. Anyway, a fair amount of wrist time and no noticeable deterioration. You would have to think, though, that perhaps straps would be outsourced from a number of suppliers using different stock and different techniques: I have a spare PP strap with quite different stitching to the fitted strap and different stamping on the liner. Perhaps there is little to be gleaned from another person's experience on this score.
Cheers,
pplater.