Description:
Problem persists in version 7.1.2.2 under Windows 10 x64 ENG, this bug has not been fixed! I create a document in *.CSV file using words in Cyrillic russian language, in ANSI and WIN-1251 encoding. I save it several times and everything is fine with encoding, all words are readable when I open this CSV file in LibreOffice few times. But by some coincidence, after saving this document before rebooting the computer (after rebooting request), after rebooting I open it and instead of all Cyrillic characters i see question marks - ????
All Cyrillic characters turn into question marks.

I lost all the russian text, I have to work in Notepad++ instead of Calc with unpredictable behavior. I lose a lot of personal time to re-editing the document.

Steps to Reproduce:
1. Create a spreadsheet in Calc with encoding parameters: ANSI, Cyrillic WIN-1251 and running on Windows 10 x64 Enterprise.
2. Enter text in Russian (in Cyrillic) into the table.
3. Save the document as a comma-separated plain CSV document.
3. Edit text, enter new lines in Russian, do not save document.
4. Restart Windows, when prompted to restart Calc will ask to save the document. 5. Press Yes and Yes again to save it in normal CSV format.
6. Reboot your computer and reopen the same document.


Actual Results:
All Russian characters are replaced by question marks in the document after opening.

Expected Results:
Show Cyrillic characters as they were saved in the document.


Reproducible: Sometimes


User Profile Reset: No


OpenGL enabled: Yes

Additional Info:
The bug does not always reproduce itself, if you just save this document and open it without rebooting, nothing changes - the characters are fine.