User [username] has messed up their journal template definition.is not mentioned anywhere in the FAQs (assuming I can trust Google).
If I am right, then I would propose to add it to FAQ #141: I tried to customize my journal using overrides and now it won't display. Why? and then rename the FAQ to I tried to customize my journal and now it won't display. Why? (i.e. remove the "using overrides"). Of course, this is just a suggestion etc.