Comment # 7 on bug 1080766 from George Anchev

I think the I have found the culprit: xdg-open (which both programs seem to
use)

Even if I try to run 'xdg-open https://opensuse.org' from console it takes
20-30 and more seconds. And just as noted: The first attempts are quite fast,
the next ones are slower and slower.

I am unable to find a solution though, so I hope someone could look into it.
All I found while searching the web was a similar issue discussed in Arch
forums in which the poster seems to have found some function in the script
which causes similar delay:

https://bbs.archlinux.org/viewtopic.php?id=184834