GetCallingAssembly returning unexpectedvalues

I have a control engine that is reflect-loading other assemblies and executing them. There is a ResolveAssembly handler in the control engine that gets called when something in the reflected assembly cannot be resolved.

The output of the two calls I am trying are

GetExecutingAssembly().FullName = "Assembly1"
GetCallingAssembly().FullName = "Assembly2"

Therefore when I call

GetCallingAssembly().Codebase

I would expect to get the file location of assembly 2. Instead it is returning the file location for assembly 1.

Why is this?