OpenStudio 3.1 erases surfaces when surface matching. Not present in OpenStudio 2.9

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See the image below for context. At the top, you'll see the model before surface matching. Below, you'll see the model in OS 2.9 and in 3.1. You'll notice how the boundary condition for the floors changes to Surface for all the surfaces except a sliver that remains adjacent to Ground.

If you look at the roof surfaces, you'll notice this sliver is now missing altogether in OS 3.1.

I'm unsure why this is happening. Here is a clue I get when doing the intersect surfaces in OS 3.1

[openstudio.model.Surface] <1> Initial area of surface 'Surface 18' 646.605 does not equal post intersection area 646.605

Link to source in C++ code as far as I can tell. Appears to have something to do with intersection code

Things I have checked:

• The order in which spaces are matched is identical
• Both versions of OpenStudio agree upon which spaces intersect.
• The OpenStudio methods OpenStudio::Model.intersectSurfaces(spaces) and OpenStudio::Model.matchSurfaces(spaces) do not resolve the issue (they made it worse somehow, not sure why).

LINK TO MINIMUM WORKING EXAMPLE:

https://github.com/jugonzal07/stack_o...

Meat of the surface code is under match_spaces on L95

def match_spaces(spaces)

    # Sort spaces for consistency between models
    spaces = sort_spaces(spaces)

    n = spaces.size

    boundingBoxes = []
    (0...n).each do |i|
        boundingBoxes[i] = spaces[i].transformation * spaces[i].boundingBox
    end

    (0...n).each do |i|
        (i+1...n).each do |j|
            next unless boundingBoxes[i].intersects(boundingBoxes[j])
            puts "#{spaces[i].name.to_s} intersects #{spaces[j].name.to_s}"
            spaces[i].intersectSurfaces(spaces[j])
            spaces[i].matchSurfaces(spaces[j])
        end #j
    end #i
end