Plenty of networking gear has trouble with it. IPv4 is just so easy to keep using and IPv6 support is often treated as an after thought. I had troubles with my

Plenty of networking gear has trouble with it. IPv4 is just so easy to keep using and IPv6 support is often treated as an after thought. I had troubles with my Ubiquiti gateway using IPv6 and the forums often recommend just disabling it. Some features don't work correctly with IPv6 even now. Google/Nest wifi did a good job of just making IPv6 enabled by default for all consumers.