Apostrophe on Linux fails to show the preview in some newer operating systems. This occurs because the WebKit backend switched to using hardware acceleration and this does not work for many users. A fix to the launching command works to bring the preview back to Apostrophe, but the same fix will not work for Epiphany.

The fix is:

 nano /usr/share/applications/org.gnome.gitlab.somas.Apostrophe.desktop 

And the modify the exec line to say the following:

 Exec=env WEBKIT_DISABLE_COMPOSITING_MODE=1 LIBGL_ALWAYS_SOFTWARE=1 apostrophe %U 

These changes will disable hardware acceleration and return the preview functionality.