brown goose fat

[timthestone]

so i had some unopened goose fat in the fridge it was bought a little bit ago but not that long, no more than a month, i was moving some things around and noticed that the bottom of the fat had gone a light brown over about half of the area, its in a glass jar so easy to see.

i was wondering what is going on, ive since opened it up and given it a sniff and it does not smell rancid, ive used goose fat in the past and never seen it go this colour.
have i got a bad batch? or is it just a natural part of the way this fat ages and ive never noticed it before?