Assuming a file with a wrong name extension (quite often .xls instead of .csv), menu:File>Properties guesses the file type by name extension whereas menu:File>Save As... indicates the actual file type that has been detected when loading the file.
Also repro using OOo 3.2.0.
Code pointer: sfx2/source/dialog/dinfdlg.cxx, function SfxDocumentPage::Reset, the relevant label is represented by m_xShowTypeFT.