Difference between Come out of the blue and Get into a blue

come out of the blue—happen unexpectedly or without warning:

• Nothing in my life ever came more “out of the blue” than my marriage.

get into a blue—(Austral. sl.) get into an argument; start a brawl:

• Are red-haired people more likely to get into a blue?

See also: get one’s blue / get the blues.