well i return to this and i think i found problem
with tcpdump i saw what exactly dokuwiki trying to do
and found this
3:12:23.860361 IP 192.168.86.2.25067 > 192.168.86.2.53: 64283+ A? www.dokuwiki.org. (34)
13:12:23.864068 IP 192.168.86.2.80 > 192.168.86.1.15346: Flags [.], ack 659, win 18373, options [nop,nop,TS val 1564803017 ecr 438481058], length 0
13:12:25.434219 IP 192.168.86.2.22090 > 192.168.86.2.53: 27168+ A? www.dokuwiki.org.mydomain.com. (42)
13:12:28.861332 IP 192.168.86.2.25067 > 192.168.86.2.53: 64283+ A? www.dokuwiki.org. (34)
13:12:35.497779 IP 192.168.86.2.80 > 192.168.86.1.44756: Flags [P.], seq 1:8268, ack 1, win 18373, options [nop,nop,TS val 2201671536 ecr 438479719], length 8267
13:12:35.497868 IP 192.168.86.1.44756 > 192.168.86.2.80: Flags [R], seq 3244303177, win 0, length 0
13:12:38.862297 IP 192.168.86.2.31188 > 192.168.86.2.53: 64947+ A? www.dokuwiki.org.mydomain.com. (42)
13:12:43.863203 IP 192.168.86.2.31188 > 192.168.86.2.53: 64947+ A? www.dokuwiki.org.mydomain.com. (42)
mydomain.com is just as example
So its probably my wrong configuration and all this time was wasted on resolving DNS
In other words its false flag :)
Only question why its trying to resolve dns query with server on site's ip, /etc/resolv.conf doesn't contain it as nameserver
Well atm, i roll back my changes in plugin manager to original and provide port redirection to emulate local DNS server.
Now its takes less then second to show "problematic" page, even with all this screenshots and update checks.
When i get more free time i will look into code to find this weird DNS issue.