Seems the LED on many Hub 3s (including my own) age badly, and the white LED drifts to a sort of murky brown-orange colour. I've got forty year old electronics that have no problems with LED colour, and I can't think of ANYTHING in our household that has ever suffered from miscoloured LEDs, so I assume that the hub manufacturer had to work very hard indeed to find a suitably shonky component supplier.
The hub's multi-colour status LED is actually a package with red, green and blue diodes, and what seems to be happening is that the blue output is fading. For the majority of customer who are using the hub in router mode the LED will be a bit dimmer and an orangey-yellow-brown depending on how much output there is from the blue diode. For those using the hub in modem mode it means the LED shows more red than magenta. It is possible that the fault is a voltage drop to the LED, or a defect within the diode itself, but either way it can't be repaired and there's not much will be done about it unless you're experiencing connection problems. If you have connection problems but they can be solved, VM will be happy to leave a hub with an off-colour LED in use. The only exception to that is where a hub in router mode shows a red LED, since that is an over-heating indicator, and in that case they'll ask you do do a reset of the hub, and if that doesn't solve it they'll send a technician to replace it (possibly with an even older Hub 3, or for a few unlucky people, an older still Superhub 2.