Article in question: https://firstname.lastname@example.org
The subject should be displayed as "Quiz 150/2020 - Niemcy i Turcja napadają na Polskę"
Instead it's displayed as "ę" (only last letter): https://i.imgur.com/Lmz3lZb.png
Will be fixed in the next release.
Fixed in v0.90.2 that was released today.
In order to get the previously downloaded headers displayed correctly, you'll need to reset the newsgroup.