SPD-SL shoe/cleat problem

That's what I thought it would be, which was why I wanted a pic of the rear of the cleat. Glad it's sorted. Strange this happened with newish cleats though. I tend to use SPD-SL cleats until all of the yellow/red rubber has disappeared (and then a few months more) and have never had any problems clipping in/unclipping....

The burr was at the front and not the rear.....rear was clean and unmarked.....up till Friday.....i had no problems either......but unclipped at the bottom of the pedal has made things even easier.......however i can unclip with the merest of inside movement...a few centimeteres and its very smooth.....odd!......ps good luck with your Miche sale.