Windows XP SP3 Home, Russian version
Default codepage is Windows-1251.
Steps to reproduce:
1. Open Writer.
2. Type any cyrillic text with DEFAULT font.
3. Copy text into the clipboard.
3. Open Calc.
4. Double-click in any cell or in formula field.
5. Paste text from clipboard.
Cyrillic encoding becomes Central-European or so: vowels with accents etc.
If you select font in Writer explicitly (even the same), then it's OK.
If you paste to Calc as unformatted text, then it's OK, too.
However, it should be possible to paste formatted text with proper character encoding.
reproduced in 3.5.0 beta 3 on Windows XP 32 bit Russian locale
*** This bug has been marked as a duplicate of bug 36144 ***