Recurrent Curl to a Virtual Server Fails on the Same Subnet

On my network, recurrent curl tests to a virtual server (10.184.1.12) only fail when the source ip is on the same subnet. (eg,10.184.1.78)

 

When recurrent curl tests are performed from any other subnet (eg,10.243.2.3 or 10.123.34.5) to the destination virtual server (10.184.1.12), they NEVER fail.

 

Are there any leads to what can warrant this.