Actually, if I understood correctly, what I believe he said was that the price data was fetched and inserted into the page by JavaScript, and the JavaScript code in question was unable to resolve the host name it needed to contact to fetch the price.The price is ASCII text embedded in the HTML page.
If the host has an IPv6 address, and if either (a) the IPv6 address isn't reachable or (b) there's something messed up in the IPv6 configuration on your end, such that no IPv6 address is reachable, then it's entirely plausible that disabling IPv6 could fix an issue like this.There is no mythical IPv6 monster eating your bytes. I hate that this "disabling IPv6 fixed it" myth exists.