Compilation optimization as well as runtime optimization can change the actual execution, as well as the call stack information constructed. So you cannot treat the numbers that seriously.
More information can be found in posts such as Scott Hanselman’s: Release IS NOT Debug: 64bit Optimizations and C# Method Inlining in Release Build Call Stacks.
It would be too difficult to troubleshoot a specific case without touching your bits. But if you know of WinDbg you might dive deeper, by live debugging the application when the exception occurs. Then you can dump the actual jitted machine code as well as other runtime information, so as to determine how the line number is constructed.