It's likely due to the fact that cellular devices don't get a direct public IP. They get an IPv4 IP address within Telus's private network and there are a few regional edge routers that all mobility devices in a given region will connect to the internet through.
When I check my mobility connection on sites like WhatIsMyIP.com, I do see an IPv6 address showing there but that is the edge router's. Sadly Apple makes it impossible to see the cellular IP on the phone itself.
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