Is there any setting in IE that would allow a page to be viewed but secure cookies are inaccessible

I have a web page at https://foobar.com/login that responds with this HTTP header:

Set-Cookie: Foo=bar; Max-Age=35999; Expires=Mon, 13-Aug-2018 00:27:53 GMT; Domain=foobar.com; Path=/; Secure

(The Max-Age/Expires is always 10 hours from the point the cookie is issued - the above is just an example)

On very rare occasion, the page appears to load just fine, but the Foo cookie is not present in the Document.Cookie presented at the DocumentCompleted event.

Logs show that when this happens, the user has accessed the correct URL over HTTPS, and the expiration is valid. If they close the application and reopen it, the very first page loaded (https://foobar.com/) will show that the cookie exists with the correct value.

So this means the web browser has loaded up the page correctly (the users cannot tell that anything is wrong), but for some reason is not considered secure enough to access the secure cookie.

The https://foobar.com site is behind a load balancer, which I suspect is part of the problem, but I'm not sure.

Can anyone come up with a reason explaining how this combination could be reached? I am unable to reproduce this. All I know is that various users are reporting it and there's no identifiable pattern to the users affected.