I guess you use Notepad++ with a russian locale. This locale has the known problem that the menu entries regarding UTF-8 in the Encoding menu are not in sync with the encoding indicator in the status bar of Notepad++.
UTF-8 without BOM:
In the Encoding menu (translated): Encode in UTF-8 without BOM
In the status bar: UTF-8
UTF-8 with BOM:
In the Encoding menu (translated): Encode in UTF-8
In the status bar: UTF-8-BOM
A fix is on its way and will be part of the next release, see here.
As a temporary workaround you could integrate the patch above manually into your russian.xml file. You can find this file in <Installation-Path-of-Notepad++>\localization.
After you did that there are 2 possible ways to activate the changed language file:
Start Notepad++, switch to an arbitrary language and then back to russian again.
Copy the changed russian.xml file to C:\Users\<Username>\AppData\Roaming\Notepad++ and rename it to nativeLang.xml.
Please note: You have to follow only one of the two steps above!