IIS Virtual Web Losing Application State

I have a website with several virtual webs configured to run as their own
applications, each with their own global.asa file. The root website merely
acts as a container for the other sites, and does not have a default document
or a global.asa file.

Once in a while one of the virtual webs loses application state, and we wind
up having to reset the application state by unloading the application or
modifying the global.asa file. I haven't been able to figure out why only
this virtual web has this problem and none of the others do. All the virtual
webs are configured the same.

Any ideas as to why this is happening? We are running IIS 5.0 on W2K.