Looking for advice on how to keep vintage seiko loom retain its white look.

I picked up a couple vaders as I just like the look. One has a great dial but the case took some knocks. The other both the case and dial looked pristine. My watchmaker was in Switzerland doing a training or certification so I used someone else. Nice guy and the watch runs fine but I’m noticing the loom plots are slowly darkening.

I’d just like to know how a watch maker would remedy this. I’m guessing it’s a gasket but I’m no watch maker. Since it’s serviced and running ok I’d like to see if it’s possible just to make the disk “air tight”. If I need to buy something myself and bring it in that’s fine. And if need be I would pay for a service again or am I being unreasonable and this is something I just have to live with. I’ll put two pictures up unfortunately artificial light of the beat up one which maintains the whiteness and the second will be the nicer case. Any knowledge or suggestions would be appreciated. I’m keeping it my watchbox with those suck up moisture packs but I’m guessing things will progress poorly when our 100% humidity comes to pass. I can move this to seiko thread if this is the wrong spot. Thanks again. And please tell me if I’m overreacting

The bottom one was just as white as the top when I bought it

Thanks, that’s what gets me though this started “after” the service so what the hec? Could the gaskets not have been installed properly? With a car or machinery I can check a repair (generally) but with a watch I am at the mercy of the watchmaker. I can’t check the work.

PS thanks I’d like to get a storm trooper eventually, well like yesterday