Leica M9 and the missing anti-alias filter

I took the picture below this morning using my Leica M9 and a 24mm/f3.8 Elmar lens. Almost every digital camera on the market uses an anti-aliasing filter while the M9 doesn’t. The lack of an AA filter normally translates into appreciably higher resolving power but may in some cases also lead to aliasing.

I took 6323 images with the M9 before this happens for the first time. I have no clue why the aliasing can be seen in frame 6324, maybe it’s the lens in combination with the structure of the wall in the background. Whatever the reason is, as long as it just happens every 6000 images i don’t worry too much.