Thanks for all the words of encouragement. Here's an update:
The ring designer wrote back...she has no idea why the micro pave part of the setting was yellowing. She reiterated that the ring was completely platinum, including the fillings. She recommended that I get the ring ultrasonically cleaned, and if the spots are still there, to bring it back to her to fix.
I took the ring to Charleston Alexander in VA and this is what happened: The technician used the ultrasonic cleaner to try and clean the ring. When the ring came out, those spots were still there. She then tried scrubbing the halo, but again, the spots were still there.
She then examined the ring with a loop, and noted that it looked like some sort of "gold" was used to solder parts of the ring. In her opinion, she said it was possible that soldering was needed AFTER the little diamonds were set. She explained to me that once diamonds are set, you should not use platinum to solder as it could damage the diamonds, so she thinks that some sort of gold (yellow maybe) was used to solder.
She said that we could have it re-plated with rhodium, but that the yellowing was likely to happen again, and we'd have to continually replate it. The other option she suggested was that we get the ring reset completely. Either way, she said that this kind of yellowing should not happen so soon.
I also contacted an independent appraiser in the DC area. She took one look at the picture I took of the spots and immediately said that gold was used to solder.
So, my FI and I e-mailed the ring designer and we're waiting back on what she says.
So sorry you have to go thru this. I would hate to have this for a ring, especially since its your engagement ring. What a nightmare!.
Its very interesting. Please keep us posted as to what the ring designer says.
I think she should redo the setting completely.