A strange error with divide surface by pattern

Found this the other day while screwing around.

Fist I'll make a sexy, dynamic surface.

Then I'll divide it up using the DIVIDE SURFACE tool.

Then I'll insert 2 solid forms, cut and create 3 surfaces.

Now, I can assign different patterns to left, center, right surfaces.

I can even flex the form a little bit and retain the multiple patterns.

But if i delete the cutting form, or try to flex too far, it loses it....so be careful!