Boundary Facets not returning all triangle vertices

Hello all, I am trying to get the surface triangulation of a shape. I have created an alpha shape from my point cloud and have plotted this shape. When I apply boundaryFacets to the alpha shape, and then attempt to plot the result points, I don't get points that cover the whole shape. Would anyone be able to shed some light as to why this is happening? I have attached a screenshot of my attempt to plot all the vertices of the triangles from the result of boundary facets. Here is my code:

flapAlphaShape = alphaShape(fv.vertices) %fv.vertices is my point cloud
figure;
plot(flpaAlphaShape)
boundaryAlphaShape = boundaryFacets(flapAlphaShape)
for i=1:size(boundaryAlphaShape,1)
   for j=1:size(boundaryAlphaShape,2)
       hold on;
       plot3(fv.vertices(boundaryAlphaShape(i,j),1),fv.vertices(boundaryAlphaShape(i,j),2),fv.vertices(boundaryAlphaShape(i,j),3),'oy','MarkerSize',5,'MarkerFaceColor','y')
   end
end

Thank you in advance for the help!