Consider the following examples: 1. Plasma/FAQ#How does Plasma work? links to the English page.
Special:MyLanguage/Plasma/FAQ#How does Plasma work? in any locale you will also be linked to the English page (broken localized links).
2. Plasma/FAQ/4.4/Configuration is valid page that can be linked, e.g. Plasma/FAQ/4.4/Configuration#Can_I_move_the_applets_on_the_panel.3F
On the other hand
Plasma/FAQ/Configuration#Can_I_move_the_applets_on_the_panel.3F points to nowhere (broken subpages).
Interestingly, Claus_chr brought up the same subject earlier this month, and I hadn't understood his point either. I have cleaned out all the no-longer-relevant stuff from Translation_Workflow and its talk page, and summarised the threads on the discussion page that are still relevant. On this particular point I've combined his and your concern. I'd like to use that page for discussions that lead to clarification of rules, so I'd appreciate it if you put a Watch on it :-)