Will it happen only on the polish language server❓
Frankly I think that I exceeded the allowed number of categories on this blog. Firstly it warned me, that a tag with Cyrillic letters may loop forever. Then it ceased to submit any posts into a tags pool at WordPress. Meanwhile RSS displayed 2 posts only.
All of this happened during a GUI rebuilding at WordPress a couple a days ago.
I wish there was a button to reset your blog to the square one❗
I just discovered, that some specific users names won’t go to the tags pool.