I am using Polish version of LibreOffice. In 3.5 or 3.6 version I can set "currency" on cell and thereafter all numbers will be displayed as currency. That is 37,82 = 37,82 zł.
In 4.0 the same method will produce outcome with needless character (apostrophe). That is 37,82 = 37,82 "zł
Format code is the same in all version. Additionally I noticed that new character appear only if user use own nativ locale options.
I can have Polish user interference and Polish currency but "locale settings" (Options > Language Settings > Languages) must be English (or can't be Polish) and then cells will display correct data.
And second reflection. This extra character appear only if I import file made in LO 3.6 (and probably older) to newer version. I can save data in 4.0 and this file will display correctly in 3.6.
*** This bug has been marked as a duplicate of bug 58179 ***