What is the bug with Cyrillic letters in links on Toaster?

Question

Toaster

The link https://www.google.com/search?q=А+Б+В+1+2+3looks like this , apparently due to the presence of unscreened Cyrillic letters in it.
The expected behavior might be one of these:

1. Re-escape these characters according to the standard.
   
2. Ignore these characters as is, without modification.
   
3. Remove invalid unescaped characters.
   

Why is the link shortened from the end by a number of characters equal to the number of Cyrillic letters instead?