It looks like the data is being pulled from Townhall, which has the same issue [1]. Wikipedia has seems to have the data [2], though the percentages are a little different (51.3% for Trump rather than 52.9%). Perhaps it is wrong because not all land in Alaska is part of a borough, Eg: Nome is listed separately, but it is just a census area.

Interesting that it seems to have the reverse trend -- Anchorage and Fairbanks went for Trump while much of the unorganized borough went to Clinton.

[1] - https://townhall.com/election/2016/president/ak/county [2] - https://en.wikipedia.org/wiki/United_States_presidential_ele...