I made a custom property that is hidden by default and applies to takeoffs.
When I select the value for the takeoff 8" Paving, it shows up as an inherited value for all items below it. Why is this happening? Especially since I don't have it set as something that will apply to items.

Hey David, this is due to our built-in inheritance from takeoffs down to items. This only happens if the property exists at the takeoff, but not at the item level. Note: applying the custom property to the item and specifying no value breaks the inheritance. T
The reason why it's not inheriting down to your linear is that we don't auto-inherit down to takeoffs.