HDRP TAA not affecting certain shapes

Using Unity 2020.1.5f1 with HDRP 9.0.0 preview-54

In the Shapes Gallery demo, using MSAA, FXAA, and SMAA seem to affect all shape types.

With TAA set to High, with TAA Sharpen Strength at 0, TAA will affect some shapes but will still leave jaggies on Polygons, Quads, Triangles, 3D Primitives, and 3D lines. Is this a limitation of TAA or due to the way those particular shapes are drawn?