I have this week uploaded a new site for a customer, who has reported that the hamburger button behaves erratically and is sometimes unresponsive. He did admit that he is using an older tablet (iPad?), so the issue may just be one of an older, unsupported browser that is incompatible with modern HTML5 code. As far as I know, he hasn't had any similar issues on a more recent iPhone, though I can't currently be certain of that.

Although, I experienced identical behaviour when testing with the native Samsung browser on my own Android mobile, though it usually works after refreshing the page. Google Chrome on my mobile appears to work fine, as does accessing the site from a PC. A friend also had a look at the site on his more recent iPad and didn't report any issues, though I don't know how thoroughly he checked.

Further, one or more elements occasionally appear to be missing when a page initially opens, suggesting that it may not be loading fully the first time, which might conceivably also be the cause of the reported hamburger button irregularities?

Has anyone seen anything similar, or has any suggestions as to the cause or a solution if necessary?

Many thanks in advance.