IBL Rendering artifacts at seams

When rendering materials that use IBL and are not completely smooth there can appear a "seam" between the north and south poles.  I suspect this is an artifact introduced when creating the convolutions for the IBL environment map when wrapping between the right and left edeges of the equirectangular HDR image.  

In the attached image you can see a grey light segmenting the reflection of the sky.  This only happens when sampling from a mip level of the environment texture, which should be one of the convolutions we created the first time the texture is used (in a compute shader).