Error sending SmartDocs API request from Dev Portal (IE only)

[#1]

When we execute one of our POST methods (SmartDocs) via Google Chrome, it works but when we use Internet Explorer, we get a 500 error.

I looked at the request via Fiddler and the requests line up except for the User Agent (IE vs Chrome). When I replay the IE request using Fiddler composer and change only the User Agent value to match Chrome, it works and I get a 200.

By the way, the 500 error response from IE.

{"fault":{"faultstring":"Execution of BuildTargetAPIRequest failed with error: Javascript runtime error: \"TypeError: Cannot read property \"length\" from null (buildTargetAPIRequest_js#39). at line 39 \"","detail":{"errorcode":"steps.javascript.ScriptExecutionFailed"}}}