tested now for 24 hours without any problem, rules and redirect work as expected, at least for dns
; <<>> DiG 9.16.8 <<>> -6 @abcd:1234:abcd::1234 google.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 20698
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1432
; COOKIE: b4478e1af406b0c4010000005f91fd06f6450beac9f0f72e (good)
;; QUESTION SECTION:
;google.com. IN A
;; ANSWER SECTION:
google.com. 264 IN A 216.58.206.78
;; Query time: 2 msec
;; SERVER: abcd:1234:abcd::1234#53(abcd:1234:abcd::1234)
;; WHEN: Thu Oct 22 23:43:34 ora legale Europa occidentale 2020
;; MSG SIZE rcvd: 83
[2.5.0-DEVELOPMENT][root@pfSense.kiokoman.home]/tmp: cat rules.debug | grep DNSv6
table <DNSv6> { 2001:470:b682:ffff:ffff:ffff:ffff:fffe 2001:470:26:5dc:ffff:ffff:ffff:fffd }
DNSv6 = "<DNSv6>"
rdr on vmx0 inet6 proto { tcp udp } from ! $DNSv6 to ! $DNSv6 port 53 -> 2001:470:b682:ffff:ffff:ffff:ffff:fffe
pass in log quick on $LAN inet6 proto { tcp udp } from ! $DNSv6 to 2001:470:b682:ffff:ffff:ffff:ffff:fffe port 53 tracker 1603300825 keep state label "USER_RULE: NAT "