Why is Orca putting supports in my screw threads?

[Astrohog]

I'm fairly new to 3d printing (3 months experience). I'm using Orca slicer with a Bambu A1. I'm getting support material in the threads of a thumb screw I'm trying to print and I can't figure why they are being printed? I have all settings at default except increasing the infill to 50%. Supports are not enabled. I'm using Bambu PLA basic with a .2 nozzle. The support material does not show up in the slicer preview. Anyone have an idea what is generating this?

[Astrohog]

I figured out how to print the thumb screw without the support. I added a cylinder support blocker on the screw. This is done by right clicking on the object and selecting the correct option from the menu while on the Prepare tab. I'm not sure how I will know I need to do this as the supports that are printed do not show up on the preview tab. Still I would like to know if there is a setting that would prevent Orca from adding the support from the start.