Tritium lume question regarding aging

[JonaG]

Hi there,

I have noticed on a few rolex models with tritium lume that sometimes there seems to be dark spot in the middle of the dots/pips. I cannot tell with most photos whether the lume is 'sunken' or the lume has fallen out. The lume here tends to be just starting to patina...so is this how the process often looks at the start? Is this a known pattern?

Sorry, I can't post pics yet. There is a GMT Master that I have been looking at with a tiny dark spot in the centre of the second hand pip. I've seen it on some subs too. I'm just worried that the lume would actually fall out and require interference at RSC.