The only page with these links is Plasma/FAQ. Aliasing of Plasma/FAQ with Plasma/FAQ/4.4 (4.3, 4.5, etc.) breaks all links on the translated versions (via Special:myLanguage). Subpages, like Plasma/FAQ/4.4/Configuration, have no aliases at all.
What is the solution for linking if we not use "/4.x/" in links? ;)
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).
Plasma/FAQ has only one purpose - to direct anyone searching to the latest version. It doesn't have any content, any sections, any subpages, so I'm surprised that even your first example works. I wouldn't have expected any links to be formulated against Plasma/FAQ at all - but against the versioned links (after all, the reader doesn't actually see that part of the link anyway). Now at last I understand where we started from :-) Yes, you are correct, I made a mistake there. Sorry about that, but I really did need to understand what you were pointing out.
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 :-)