Could Debian just remove the faulty patch upstream_remove_part_from_KXMLGUIFactory_on_exit and create 4.14.2-3?
I have checked it and this patch actually introduces version 4.14.3 without naming it so, since it is the only difference in ark between 4.14.2 and 4.14.3. The upstream fix is just removal of this patch, so removing it from Debian package seems like the correct solution.
