AOS crash when attaching a receipt to Expense Report in Enterprise Portal

During an AX 2012 R3 installation, an issue was encountered when testing the Expense Reporting functionality through Enterprise Portal. A user could enter an expense report just fine, however once they attached a receipt to the report, Enterprise Portal would go down and be unavailable.

The AOS service which EP was pointing at crashed as a result of attaching a receipt to an expense report. What we found was that the 'Enable the hot-swapping of assemblies for each development session' checkbox was CHECKED on the AOS Server Configuration. Once a new Server Configuration was created with this checkbox off and AOS restarted, the errors no longer occurred.