Hi and sorry for the delay! I was on a summer vacation and, unfortunately, I wasn’t able to reply earlier.
Not sure why this happens for you – normally on mobile the +/- button functions just as a toggle for the sub menu so clicking it, shouldn’t activate the link. You can check this on the default demo page:
So I guess there is something specific on your pages that breaks this behavior but it’s very difficult to guess what it might be without being able to test your code. So, if possible, please post some kind of the demo that I could test and investigate the issue.