Missing letters in transliteration

Hi, I'm trying out the platform, but I'm noticing problems with transliteration.

1. When I write a product title in Bulgarian (Cyrillic), the SEO address is translated automatically, which is nice. But the system "eats" some of the letters, perhaps those that it cannot translate correctly. One of these letters is the Bulgarian letter "Ъ".

2. When I create a list of attributes, if the attribute starts with the Bulgarian letter "У", there is no way to add the product to the cart, regardless of whether the attribute is selected or not. There is no chance that the product will be added to the cart. For example, if the attribute is called "Услуги" translated into English as "Services", there is no way to add a product to the cart, because it says an error. However, if I change the first letter to some other, then there is no problem. When I change the language to English everything works.

Apparently the platform has some problem with transliteration, but I can't find where it is.

Check this file starting at line 69 to understand what it does to special characters for some languages.

[url=https://github.com/litecart/litecart/blob/dev/public_html/includes/functions/func_format.inc.php]https://github.com/litecart/litecart/blob/dev/public_html/includes/functions/func_format.inc.php[/url]

Okay, but can i add my language at that file, and it will work?

Edit: Yeah its work, thank you!

But for the second question I still can't find a solution. I don't understand why only one letter can be a problem with attributes...