Thankyou, that’s helpful.
Settings->general shows https://
I’ve cleared the cache.
and I’ve already fixed it on our site by forcing all traffic (except wp-admin) through http with a redirect.
Previously the site was accessible through https and http and was behaving weirdly, but your explanation for the files being built by the first visitor makes perfect sense.
it would be nice if I could serve the site by either http or https and for it to work correctly, so if it could be fixed in due course, I’d appreciate it.
Thanks