Solved! Should’ve guessed the slug thing, damn. Thank you so much. Donation incoming. Sorry I can’t give more at the moment. Best of luck!
Hi, thanks for responding so fast.
Yes, latest version of the plugin, downloaded it here.
You were right in your intuition. Names were plain text, but it was cyrillic. Tried latin, and it fixed everything. Problem is, my site is in Russian. Is there a way to bypass this limitation? I’d be happy to donate (what you think is reasonable) if you could find a way to make this plugin work with cyrillic text.