Joists are rarely continuous over the top of a wall instead they are often spliced over the top of the wall as dimensional lumber only available in specific lengths.
Truss roof load bearing wall.
Load bearing interior wall under truss roof.
If there is a truss over the wall the wall is probably not load bearing since the truss bears the load.
With your trusses spanning the exterior walls for the full run of the house no interior walls will be load bearing the splices on trusses are engineered to be self supportive according to the plate sizing the fact that they land over an interior wall has nothing to do with that wall being load bearing trusses are engineered to span exterior wall to exterior wall self supporting.
An example of a load bearing wall call be seen on the right.
Having said that i d still just put a dbl 2x10 w ply flitch header in call it a day.
If truss was build as a one piece truss it shouldn t be center bearing.
Engineered roof truss systems may be designed to eliminate the need for load bearing walls or change where the bearing walls are located.
For example a gable end truss may be designed with support members that transmit the roof weight load outward to the side walls allowing the end wall directly below it to have breaks or openings in it that would otherwise be impossible.