No, no color change, to be honest I was a bit afraid for that as the lighter the strap the better it looks
On my 389
The same was done with my Simona all black Diver strap and my wife's Simona Red Diver strap, no change. The only thing that happens is that the strap gets even softer than it already is.
Dutchman living in India, Panerista since 2014 and learning
PAM389 and PAM372 and a bunch of straps