Hello, I installed flatpak, added Flathub, restarted my system but I get
permission error when it tries to download a runtime:


flatpak install flathub com.valvesoftware.Steam 
Required runtime for com.valvesoftware.Steam/x86_64/stable
(org.freedesktop.Platform/x86_64/1.6) is not installed, searching...
Found in remote flathub, do you want to install it? [y/n]: y
Installing: org.freedesktop.Platform/x86_64/1.6 from flathub
[####=               ] Downloading: 31,3 MB/185,7 MB (978,4 kB/s)              
error: While pulling runtime/org.freedesktop.Platform/x86_64/1.6 from remote
flathub: Writing content object: open(O_TMPFILE): Permission denied


I found other users had likely the same issue and it seems to have been fixed
in a newer version:
https://github.com/flatpak/flatpak/issues/1507

I also tried reinstalling flatpak (with a reboot) and updating my system since
encountering the error but I still run into the same issue. I am currently on
Tumbleweed 20180520

Maybe updating flatpak would be a good idea, the current version is from
February and there are plenty newer releases available.

Thank you for any help!