KDE Plasma software update applet throwing an error (couldn't resolve proxy: HTTP_PROXY)

Yes, that’s surely different from me. In my case both applet and pkcon says they can’t download repo metadata because they can’t resolve HTTP_PROXY that I didn’t set. Logging out and in solves that… until next reboot.

I recently disabled autologin without password but just enabled it again. On top of it, I installed the 20200701 Tumbleweed update.
Now problem disappeared (I hope forever).