That’s some legacy stuff that shouldn’t even be used anymore but for some reason are activated by default. If you’re using the enhanced input system, in your project settings disable entirely the use of input scale, it leads to incomprehensible rotation bugs which doesn’t make any sense if you try to limit some rotation on you’re character and especially more of a pain if you only work with blueprint and do not go in the src code to check what’s going on. (I’ve spent way too much time trying stuff out only to realise this deprecated feature is active).
Scale the input using modifier with the enhanced input system, or straight out implement you’re own sensitivity system, and keep that scaling to 1.0.