We'll investigate. My guess is that one file has an UTF8-BOM mark, and the other does not have an UTF8-BOM mark. If so, we will fix this.

Looks like there was diffrent procedure when file is saved from editor using "Save as" function and when saved for any compare function ( here is some kind of worng and not needed conversion from already UTF8 in edit window to ANSI ). My ukrainian letters are converted to question marks, same when there is wrong NLS_LANG ( which shouldn't be used when dealing with unicode, but that's anoter story )