Interesting.
Looks like the $300 travel credit isn't so much based on calendar year, but rather the month the statement will post.
I just had my statement close yesterday, 12/3, which means my next statement won't close till 1/3, and my $300 travel credit reset and I saw a $30 credit for a charge that posted on 12/3. I've already used up my $300 credit.
Also noticed that the $300 reset on the tracker within the UR site.