OVR_ASSERT on ovrHmd_GetLastError

I'm having trouble calling ovrHmd_GetLastError in debug mode; it triggers an OVR_ASSERT from LibOVR\Src\Service\Service_NetClient.cpp line 614:

if (!bsOut.Read(Hmd_GetLastError_Str))

I don't get the assertion if I pass in 0 for the ovrHmd parameter (which according to the docs should return global errors). If I pass in the pointer returned from ovrHmd_Create I get the assert.