I am having this problem for years already and therefore can't use the korganizer's journaling...
When I choose the "New Journal" action I always have the first "Calendar" item empty.
All the rest new actions always do see my gmail calendar.
As the problem moves from FC20 to FC25(!!!) already, I suppose there is some setting/rc which blocks the calendar for journals, but where!?!?!
Please, any hint/help will be HIGHLY appreciated!