I found out that I have been making my purl stitches incorrectly. My knit stitches are correct, but it seems I have been wrapping my yarn around the needle clockwise instead of counterclockwise when purling. I guess this is call the "Combined Purl" and results in a twisted knit stitch. Don't know how or why I came about doing my purl stitches this way. I swear that was how the instructions I learned from showed how a purl stitch is done. It seemed very logical and very natural for my hands and fingers to work the yarn this way (I am an English knitter).
Not a HUGE deal though since I really haven't done any flat knitting in AGES!!! Any purl sitches I do in the round are for ribbing and the knit stitch is never seen and I see no noticable difference in the purl bump on the right side of the work. Nor have I noticed any differences in my right or left slanting decreases when working in the round.
I do have several pieces of an unfinished ribbed sweater stashed in the closet, waiting for me to complete the second sleeve and seam everything together. I haven't touched it in at least six months. THese were all done as flat pieces and I guess every other row of knit stitches on the right side of the fabric are twisted. Still, no huge deal since I really do like the look of the sweater and it's such a fine guage I don't think anyone except the pros will notice, and only if they're looking VERY closely at the work. I will have to remember that when I do finish the second sleeve that I continue to do the "Combined purl" so that it matches the rest of the work.