There is a problem with displaying Cyrillic characters (Ukraine, Russian, Belarusian) from XML documentation in hints in the code.
Screenshot 1 shows how the method source code (method declaration) with XML documentation looks and appears (correct).

Screenshot 2 shows what the tooltip looks like in other code that uses the above method (not correct).

All code is located in one assembly.
An additional complication of this problem is that it does not always occur. Once I load the project - the problem described above is there. Another time I load the project - there is no problem, all the tips are displayed correctly. I've wanted to send you this issue for a long time, but I couldn't always reproduce it. Now it has appeared and I made screenshots.