Stracing the app reveals what the problem is:
O_RDWR) = -1 EROFS (Read-only file system)
the app is trying to open the template file in read/write mode, but it's
in a read-only location.
You received this bug notification because you are a member of Desktop
Packages, which is subscribed to libreoffice in Ubuntu.
[snap] failure to open templates from startcenter
Status in libreoffice package in Ubuntu:
(initially reported here: https://forum.snapcraft.io/t/libreoffice-
When trying to open any template from the startcenter, the following
error is displayed in a message box:
General input/output error while accessing
However the same templates can be opened and used from the individual
apps, e.g. from impress for that Blueprint_Plans template.
To manage notifications about this bug go to:
Mailing list: https://launchpad.net/~desktop-packages
Post to : email@example.com
Unsubscribe : https://launchpad.net/~desktop-packages
More help : https://help.launchpad.net/ListHelp