Could be a bug, could be a glitch, just thought id let you know.
Last night I had a couple of occasions when I had 2 fastest times at the same time, but never saw the combination jerseys in the game.
I started out with green, I then won the KOM, but only the green showed up on my back.
After the KOM attempt, I then went on to try for a fast lap and won the orange. During that lap I lost the green, but the polka dot never appeared even though I still had the fastest time. I completed the lap with the fastest time and so gained the orange jersey, but at no time did i see a polka dot.
I held the KOM until I logged out after 1h30 mins but never once saw the polka dot jersey in any form. there was no icon for it either when riding on the other direction.
Hope this makes sense.