This almost rises to the level of a bug, because it is a major impediment to use in certain situations.
In any kind of English manuscript, when a speaker is quoted for more than one paragraph in a row, ONLY THE LAST PARAGRAPH CLOSES THE QUOTATION MARK. LanguageTool falsely expects every open quote to have a matching close, but in long quoted passeges, this causes it to falsely flag every open quote until the final paragraph. For anyone writing a novel or screenplay, that makes this rule all bug useless. Invariably, even if we try to pay attention, we eventually give up and just ignore all the quote related warnings or turn off the rule.