URL address of the page where you encountered the problem

https://finto.fi/yso/fi/index/%25C3%2584

Description of the problem

Steps to produce the problem, and the expected outcome after it has been fixed

When viewing YSO at finto.fi, the alphabetic tab doesn't work with letters É, Š, Å, Ä and Ö. YSO has concepts starting with these letters, but none of these show up. Only the diacritic letter Ž gives results (visible when YSO content language is English). Non-diacritic letters seem to be working fine.

Additional information (e.g. screenshots) about the problem

The browser you used when the problem appeared

Tested with Firefox and Chrome with YSO content languages Finnish, Swedish and English. Same results.