Can't set long non-ASCII nickname

[kunitsyn]

"Profile name" text box in Steam settings allows typing up to 32 characters, regardless of whether they belong to ASCII or not. But if I type long enough nickname that consists of Cyrilic letters, I'll get an unexpected error: "Failed to change profile name. Please try again in a few minutes". Or I may not see this error, but my profile name won't be actually changed (and if restart Steam client, I'll see that it stays unchanged).
For example, "abcdefghijklmnopqrstuvwxyz012345" is allowed, but "абвгдежзийклмнопрстуфхцчшщъыьэюя" is not.

[eiglow]

I just tested this now. "abcdefghijklmnopqrstuvwxyz012345" is allowed but "абвгдежзийклмнопрстуфхцчшщъыьэюя" is apparently still not allowed. However, removing one character from the latter allows it to be used.