Ці то модуль Grammar не працуе як сьлед, ці то нехта яго няслушна навучыў. Месны склон: «аб кім/чым — аб/у Вікіпэдыі». Пакуль замяніў на родны.
Nope, it's just a grammar nazi thing, nothing common with nazism itself, don't worry :)
By the way, here's the patch that fixes the reported issue. Could you review and merge it later this day? I'm not pushing it because it's undergoing 3rd party review at the moment, just in case I screw up again, as this fix actually fixes the previous correction.
Or let me just add you to the list of reviewers as soon as the list of forms is checked by a person.