に限ったことではない・に限らず: the difference
Meaning
Not limited to, Not restricted to, Not only
Past papers
Example
浮気をするのは男性に限ったことではない。女性だって浮気をする。
Cheating isn't limited to men. Women cheat too.
に限らずN2
Meaning
Not just, Not only… but also
Past papers
Tested once in past papers
Example
ラッシュアワーに限らず、電車にはあまり乗りたくない。
Not only during rush hour, but I don't really want to ride the train.
How to tell them apart
「〜に限ったことではない」: at the end of a sentence; states 'it is not just A'.
「〜に限らず」: in the middle of a sentence; leads on to a wider range, 'not only A but also B'.