Description of the Issue

I saved with only 今 (means "now" in Japanese) on the first line with UTF-8. Then, I re-opened the file. However, the file was opened as TIS-620.

Steps to Reproduce the Issue

1. [File] ->[New]
2. type 今 on the first line
3. save
4. [File] -> [Reload from Disk]

Expected Behavior

open the file as encoding UTF-8

Actual Behavior

encoding was changed to TIS-620

Debug Information

Notepad++ v7.5.8 (64-bit)
Build time : Jul 23 2018 - 02:06:36
Path : C:\Program Files\Notepad++\notepad++.exe
Admin mode : OFF
Local Conf mode : OFF
OS : Windows 10 (64-bit)
Plugins : ComparePlugin.dll DSpellCheck.dll MarkdownViewerPlusPlus.dll NPPJSONViewer.dll PluginManager.dll PythonScript.dll mimeTools.dll NppConverter.dll