Sandbox problem with NSTask calling an executable outside the App Bundle

Does anyone know why in Mac OS X 10.11.2 you can no longer use NSTask to call a binary execultable outside the App Bundle with Sandboxing turned on? When I try to launch the binary executable the user has chosen via their allowed Sandbox entitlements, I get: "caught non-fatal NSInvalidArgumentException 'launch path not accessible". However, the launch path is accessible. With the Sandbox turned off, NSTask can launch the executable perfectly fine and it worked fine in 10.11.1 with the Sandbox on.