I am running Lubuntu 12.10 amd64 bit, with the default version of PCManFM installed, PCManFM 1.0.1
When I view my home folder with the "Thumbnail View" option from the view menu, some icons are not rendered aligned with the grid. I only saw this happening with my home folder, possibly because the folders ".nv" and ".pki" have short names?
Steps to reproduce:
Go to home folder, and set the View option to "Thumbnail View" and check "Show Hidden".
Try re-sizing the window horizontally until some icons render misaligned with the grid.