I just updated my sites to the latest marketpress version and in one instance so far, the default menu added in a custom menu causes a fatal error php memory max usage error. The site memory usage was already configured at 512 MB and routinely uses 50-60MB. When I upgraded the memory to a max of 800 MB and refreshed the site, the same error maxed out the 800MB. Similarly, the same thing occurred when I upgraded to 1200MB. The error referenced navigation.php for the existing theme. Coincidently, I thought the theme was broken because when I activated 2011 or 2012 default theme, the site loaded fine but this turns out because when activating a new theme, you have to still activate the primary menu which would have caused the same error.
It turns out that I had to delete the default Store menu item in the custom menu and create a tree of menu items using the custom link option under the menu.php area. I was able to recreate the menu item “Store” with subpages Products, Shopping Cart and Order Status by referencing those pages directly as a custom link rather than the default.
Is it possible that this is a bug with the latest version? The site seems to be working fine with this work around in place. I have to diagnose my other sites to make sure the same thing hasn’t happened there as well.