I think you hit the hammer on the nail here. 99% of all Albino errors are due to sun discoloration. 
Although the card itself usually is slightly lighter as well, with the early WotC cards the border discolors way faster than the rest of the card, starting pink and becoming beige when exposed for an extensive amount of time.
Here an example of a Pikachu I own with pink borders, but at the top-right it still has yellowish borders:
Here another one that was exposed for a longer period of time, making the card overall lighter, and the border more beige instead of pink. With this card a small portion (bottom-left) is not very discolored as well.
And when a card is sun-discolored in an all-year-around sunny area on purpose every day for more than a year, it ends up completely bleached:
Some other sun-discolored cards I own:
Jumbo with partial Albino borders:
Bunch of other sun-discolored cards (with non-discolored one in the middle as comparison):
And my second on-purpose sun-bleached card, which looks pretty cool with the blue background:
Anyway, sorry for all the pictures. As I mentioned, in almost 99% of the cases it is discolored by the sun. I have seen some examples that were short on ink and were pulled out of the packs like this (most likely). Here is one of the two examples:
Unfortunately I can’t find any pictures of the Albino Zapdos that former member @darkrai owns. Does anyone still has any pictures of this discolored Zapdos somewhere?
Greetz,
Quuador