CM1000 ipv6 only

Hi all -- my CM1000 cable modem is reporting the following:

I'm assuming "IPv6 only" may be related to my observed speed and connectivity performance degradation for specific sites - I would maybe expect to see something more about IPv4 support as well.  I have tried rebooting, factory resets, and have tried to work with the ISP (who said they don't have the appropriate access to change settings on my cable modem).  Should I either be seeing something else besides IPv6 only that implies additional IPv4 support?

thanks,

rcmlynn