[iDRAC] redfish: often get an exception "The server committed a protocol violation"

Hey all,

some basic information:

• PowerEdge R630 - iDRAC8 - V2.30.30.30
• using a custom certificate on iDRAC
• client ist trusting the certificate (cert chain ok)
• using PowerShell V4.0 

I get very often (~40-50% of calls) an exception while calling the redfish api with PowerShell. Even if the interface does not require authentication. Every time I call the same URI. 

The exception message:
The server committed a protocol viloation. Section=ResponseStatusLine

Also about 1% of calls I get the exception:
The request was aborted: Could not create SSL/TLS secure channel.

The basic powershell command:

Invoke-WebRequest -Uri "11.22.33.44:443/.../v1" -Method Get -Headers @{'Accept'='application/json;*/*'} 

I attached a PowerShell sample script to show you how I call the API. (Remove the ".txt" extension).

Is this a Bug or I'm doing something wrong?

Ulli