How is なにか used in this sentence? It is used twice, but it doesn't seem to mean "something" in this case. The sentence is from a story called "小学生ときつね"
At its most pure, なにか on its own does mean "something/anything/whatever". However, it can also be used generally to express many forms of vagueness, typically indicated by the English marker word "some", especially when combined with the true subject of the statement. Think "some kind/sort of [thing]", and "somehow" as a lead-in.
"John bought something"
"John bought some book"
"This is incomplete somehow"
(The source also demonstrates informal/shorthand/dialect usage なんか)
You can think of the general purpose of なにか as the concept "[something] I can't quite put my finger on".