Hello @Patrick-Edouard, this issue is already being tracked at https://github.com/ValveSoftware/steam-for-linux/issues/4800. Closing as a duplicate.
Thanks for the update.
Seems to be related indeed though Dota is installed on my SSD which is a EXT4. Don't know why it tries to update it on the proton library.
Hello and thanks for all your work on this new feature.
Unfortunately it seem installing a game with Proton broke my (native) dota2 updating.
I'm running Fedora 28, OS and main steam library (where my dota2 is installed) are installed on a SSD. I have a secondary steam library on a mounted hard disk and made a new library on the same disk for Proton games (can't use the same as native games?).
Now there is a Dota2 update, and when it finishes I get an error message (https://imgur.com/PgB9Gdj) mentionning dota2 and my Proton library (where dota is NOT installed).
By launching steam from a terminal I can see the following trace:
Thanks;