If you click “Custom” (instead of “Recommended”) you can scroll down and view all the nit-picky settings (well… all the settings that aren’t hidden).
There is a “Support” section.
The tool-tips are pretty good… hover over and it should explain what the setting does.
There are probably two key settings to look at.
The “Support Placement” box will have the choices of “touching buildplate” or “everywhere”. “everywhere” means it will even fill in holes or gaps in the middle of a part. “touching buildplate” means it will build up from the build plate… but will NOT make support in the middle of a part if the bottom of that support wouldn’t touch the build-plate.
Check your “Support Overhang Angle”. Most printers can deal with a 45° overhang and not need support. But maybe… a 70° angle is too much and that needs support. If the angle is set too high, then support wont be generated in areas that only have moderate overhangs.
There are loads of other settings, but these two can be reasons why you enable supports, but supports are generated.