Nautilus constantly popping-up autofs mounts in file browser

Binary package hint: nautilus

I have installed autofs, and have two shares exported on my server by NFS. On the client machine, both shares mounted by autofs appear on the desktop (this appears to be new in Hardy). The problem is that autofs remounts the shares every five or ten minutes, which causes a very odd sequence of events:

 - autofs shares momentarily disappear from the desktop
 - Both shares will open, each in a new file browser window.
 - If the share is already open in a window, the error message 'Couldn't display "/net/[server]/[share]" - The location is not a folder.' is also displayed. I am assuming this is because the share was remounted while the file browser was pointed at it.

These pop-ups accumulate, and if my machine is left unattended for a long period, I will return to find dozens (sometimes hundreds) of open file browsers - I generally need to restart gdm (using crtl+alt+backspace) when this happens because the system has become rather unstable.

I have attempted changing the "Removable Drives and Media" preferences by deselecting "Browse removable media when inserted", but this does not fix the problem.