There was a major spelling reform introduced in Poland, starting on the 1st of January 2026, which means that now LanguageTool will sometimes introduce incorrect changes or try to correct proper capitalisation to incorrect one.
Is implementing correct Polish spelling on the roadmap? There is a github issue created but no responses: Advice needed - Polish orthography changes from Jan 2026 · Issue #11684 · languagetool-org/languagetool · GitHub