Well something out there (perhaps the DNS server for mydomain.com) is answering the AAAA query:
13:04:07.910775 IP tiger.mydomain.com.62310 > router.mydomain.com.domain: 27878+ AAAA? panda.mydomain.com. (39)
13:04:07.924733 IP router.mydomain.com.domain > tiger.mydomain.com.62310: 27878 1/1/0 CNAME mydomain.com. (123)
That means it asked for the AAAA record for panda, and got back that result is a CNAME for mydomain.com
And then it asked for a AAAA record for mydomain.com, and AAAA for panda.dolcera.net…
13:04:07.924964 IP tiger.mydomain.com.55111 > router.mydomain.com.domain: 55178+ AAAA? mydomain.com. (33)
13:04:07.939512 IP router.mydomain.com.domain > tiger.mydomain.com.55111: 55178 0/1/0 (103)
13:04:07.939945 IP tiger.mydomain.com.62372 > router.mydomain.com.domain: 25705+ AAAA? panda.dolcera.net. (35)
13:04:07.953756 IP router.mydomain.com.domain > tiger.mydomain.com.62372: 25705 NXDomain 0/1/0 (97)
…and got back an answer that they don't exist.
Then finally asked for an A record for mydomain.com...
13:04:08.289062 IP tiger.mydomain.com.51172 > router.mydomain.com.domain: 23562+ A? mydomain.com. (33)
13:04:08.308518 IP router.mydomain.com.domain > tiger.mydomain.com.51172: 23562 1/0/0 A 98.xxx.xxx.xxx (49)
…and got back what is presumably your WAN IP.