I use LibreOffice 5.0.6.
I have a spreadsheet with equations cross-linked among the various sheets in the spreadsheet.
Within a sheet I type equations without any reference to the sheet name itself, such as “=B3^2”.
However, after some time, the equation is automagically replaced by “=SheetName.B3^2”.
Obviously the ‘SheetName’ is redundant, as the equation is in the very same sheet where B3 is located.
I have no idea what triggers this change or how to revert it (apart from editing all equations manually again).
Of course the equations are still working correctly, but they become so much longer and difficult to read…