These are little gas/air bubbles, with the angel of the crystal it looks big but it isn't. Nothing speculative here and these are no deffects as every crystal on Grand Seiko has it probably
I own a GS SBGW 231 and SBGW 255. Basically they are same except the latter is limited edition. Curiously I found some “marks” on both watches in between the bezels and the sapphire crystals. A purist also told me that he found the same marks on his SBGW ...
We can't give you a definitive answer, and it's not very helpful to guess or rant about it. I'll see if I can dig up anything. But it would require much sharper pictures - can you try to take some more? Cazalea