Description of the Issue

When using the Auto-Completion function some words are duplicated.

Steps to Reproduce the Issue

1. Download a fresh portable version of Notepad++
2. Make sure the Word completion is selected in Settings > Preferences... > Auto-Completion
3. Open the english.xml or bulgarian.xml file from localization folder of Notepad++
4. Start to type iss or it in english.xml or прое in bulgarian.xml

Expected Behavior

I expect to see not duplicated words in the pop-up window

Actual Behavior

In the test case when type iss or it in english.xml the word it is duplicated. Same is the word them when type the. In bulgarian.xml the word проекта is duplicated when type прое. Same is the word права when type пра. I use bulgarian.xml for test the cyrillic.

Debug Information

Notepad++ v7.9.5   (64-bit)
Build time : Mar 21 2021 - 02:13:17
Path : C:\Users\Home\Downloads\npp.7.9.5.portable.x64\notepad++.exe
Admin mode : ON
Local Conf mode : ON
OS Name : Windows 7 Professional (64-bit) 
OS Build : 7601.0
Current ANSI codepage : 1251
Plugins : mimeTools.dll NppConverter.dll NppExport.dll