Thanks.
Well, I can't tell you what modes the file is opened in, because thats buried in the Glib/GIO libraries we use.
The library used for reading is chosen by the settings for saving, what are the `preferences->various->use_gio_unsafe_file_saving` and `preferences->various->use_atomic_file_saving` settings?
Atomic off, GIO on will use GIO, any other combination will use Glib. You could see if there is a difference between them.