Is that in the US? In my Eastern European country, IPv6 has not become directly available to mobile customers. One of our major ISPs began offering IPv6 addresses for fiber customers over half a decade ago; all the customer needs to do is set up PPPoE on the router and the connection automatically gets both IPv4 and a couple of IPv6 addresses. But if you add mobile internet to your contract with that ISP, that mobile connection still only provides an IPv4 address that I assume is NATed to hell. The same is true of internet connections through a large pan-European mobile provider here.
I don't think that Canadian ISPs are in on this. In particular, almost all Canadian mobile customers are on Bell, TELUS, and Rogers. I'm on TELUS right now and I fail test-IPv6.com. Telus and Bell actually share much of their mobile network so I'm not sure Bell would fare better. And I was on Rogers as recently as 6 months ago and they didn't have IPv6 either. And my home ISP, a small fibre ISP, doesn't have IPv6.
I'm on Fido/Rogers in Quebec/Ontario, and they have had IPv6 enabled for 1-2 years. Make sure that your APN settings enable IPv6 (in Android, there's an option for that).
Mobile is the main reason why Canada is >15% adoption on google-stats [1]. On DSL/cable, Rogers and Cogeco provide IPv6, as do smaller re-sellers such as Teksavvy on DSL, but otherwise big players such as Bell and Videotron have been dragging their feet and giving lame excuses.
I tried a few months ago and can enable IPv6 on my LG V20 (on Telus LTE) and it does indeed pick up an IPv6 address but test-ipv6.com complains of MTU problems.
Sites did load over v6 but it was slow compared to v4.
LTE or DSL? I'm on LTE in Vancouver and it fails (and has consistently in the last 6 months).
Are you in Calgary? Telus always rolls out experiments in Calgary first. For example, until recently their only deployed GPON networks have been in Calgary subdivisions.