Sure, it’s all just a theory based on moisture turning lume mouldy/black, and an observation that the hands furthest away from the dial (hence nearer the crystal) do so before the hands below it, as well as in the hands whose lume extend almost to the center of the dial, the 'blackness' moves from the center (where its connected to the movement) outward...
Or at least this is one of the things seen on old speedies with factory original hands, whose lume age is the same and application uniform (unlike the watch in the OP) ... but not all speedies exhibit this behaviour ...
Naturally watches whose hands and dials are relumed by different factories (i.e. UV test shows clear difference in glow, as well as day-light inspection shows clear difference in color (modern Oris is an example i can think of)) may not necessarily work exactly this way, but the context here is Speedies...
And then moisture also depends on climate etc etc etc. I stick by this theory, it serves me well.
Edit : FWIW, vintage Seiko exhibits similar behavior.
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