setAutoFilter creates a bloated HSSF Excel 97 file (~130kb without AutoFilter to ~830kb applying setAutoFilter to a worksheet with 22 columns and 288 rows). The resulting workbook displays the AutoFilter correctly, but the menu option Data->Filter->AutoFilter does not turn the AutoFilter off. The "same" code creates am XSSF workbook without bloat, and the AutoFilter behaves properly (On/Off) when the workbook is opened in Microsoft Excel.
Despite being able to consistently reproduce this issue previously, I am now unable to do so. setAutoFilter is now behaving for me with both HSSF and XSSF.