\rightharpoonup spacing not correct

[kekearif]

Hey, I need to add the rightharpoonup command. I am modifying MTMathAtomFactory like so:

+ (NSDictionary<NSString*, NSString*>*) accents
{
    static NSDictionary* accents = nil;
    if (!accents) {
        accents = @{
                    @"grave" : @"\u0300",
                    @"acute" : @"\u0301",
                    @"hat" : @"\u0302",  // In our implementation hat and widehat behave the same.
                    @"tilde" : @"\u0303", // In our implementation tilde and widetilde behave the same.
                    @"bar" : @"\u0304",
                    @"breve" : @"\u0306",
                    @"dot" : @"\u0307",
                    @"ddot" : @"\u0308",
                    @"check" : @"\u030C",
                    @"vec" : @"\u20D7",
                    @"widehat" : @"\u0302",
                    @"widetilde" : @"\u0303",
                    @"rightharpoonup" : @"\u21C0",
                    };
    }
    return accents;
}

This returns the correct symbol when the command is used on its own.

However if I try to accent something with it the vertical spacing appears to be incorrect. e.g.

How can I go about adjusting this? Am I on the right track here?