HexEdit misinterprets file and saves incorrectly

[Gordo2022]

Hi,

I have a problem with editing a specific file with N++ in the HexEdit view, where the file content that I see in the Hex preview is not what actually gets saved. Please refer to this link:
(notepad-plus-plus/notepad-plus-plus#12647 (comment))

To recreate the bug:

1. The original file made_with_hxd.txt looks like this:
   

2. open the file you created and switch to the HexEditor view (leave at OEM866), it now looks like this:
   

3. correct the bytes in the file that appear to have changed from the original
   

4. Save the file and close it.

5. Now if you re-open the file in N++ or Hxd (HxD shown below), it looks like this (the file has been altered):
   

Thank you!