I have asked you all, who have this issue to report it. I haven’t reported anything since I do not have the mentioned issue.
UPDATE: hmm, I checked again and I have this issue as well. It is not as bad as the reporter here with 40s, but it definitely loads slower than other tabs in the firewall section, although I do not have any port forwarding so the page is a kind of empty. Other tabs load in 1s, this one loads in ~15s