It's nice to see an IPv6-enabled DNS report tool, but I've found an issue when testing some domains.
For example, my ISPs domain has some unexpected errors
https://network-tools.webwiz.net/dns-report.htm?domain=aa%2Enet%2Euk&mail=false&IPv6=true
As far as I can see, the problem relates to incorrect shortening of addresses. Specifically, more than one run of zeros are replaced with double colon.
e.g.
primary-dns.co.uk
[2001:8b0::30::51bb:1e29 - No Glue] [TTL: 172800 - 2 Days]
secondary-dns.co.uk
[2001:8b0::81::51bb:5120 - No Glue] [TTL: 172800 - 2 Days]
Note the double-colons both after 2001:8b0, and also after the 30 or 81. These are not valid, as multiple double-colons are ambiguous in IPv6 addresses.
This is more than just a display error - these incorrect addresses appear to be passed into later tests, making them fail.