I thought I had it nailed down to line count but this proved to be false.
More tinkering revealed that the TEXMAP portion of the part *must* be the first geometry in the part. Once I moved the TEXMAP to the beginning of the part, the image generated fine. This is not required by spec but will prevent the image creation issue that has been happening.
More tinkering revealed that the TEXMAP portion of the part *must* be the first geometry in the part. Once I moved the TEXMAP to the beginning of the part, the image generated fine. This is not required by spec but will prevent the image creation issue that has been happening.