LM3S9B92 C5 flags external reset upon power-up

I'm using an LM3S9B92 C5 and am facing the same problem as another poster had with a different part ( http://e2e.ti.com/support/microcontrollers/stellaris_arm/f/471/t/45565.aspx), namely power-on reset also flags an external reset in the SYSCTRL_RESC register

Here's the code I used to detect this behavior; it's right after the UART init code:

====================================
#if 1            // UART/RESET test

        {
            volatile int rv;

            rv = ROM_SysCtlResetCauseGet();

            UART_IntOut( rv );

            *((int *)(SYSCTL_RESC))    = 0x00 ;
            while (1) ;
        }

#endif
====================================

Each power-on reset gives me a 0x03 (I watch it on a scope) rather than the expected 0x02

Hitting the external reset repeatedly gives me the expected 0x01's

No mention of this behavior in the C5 errata as far as I can tell.

Any clues?