Very odd sprintf() issue

ARGH!

Everywhere in my thousands-of-lines code that I use sprintf(), I have no issues..

..except ONE function.  Here's the function:

void UpdateTestStatus(unsigned char *Payload)
{
    unsigned int nTemp;
    char pMsg[60];

    LCD_Clear(0x0, TRUE);

    GrContextFontSet(&sContext, &g_sFontCmsc12);

    nTemp = (Payload[0] << 8) | Payload[1];       // Cycle count
    sprintf(pMsg, "Cycle Count %u", nTemp);
    cdcSendDataInBackground((uint8_t*)pMsg, strlen((const char *)pMsg), CDC0_INTFNUM, 1);
    GrStringDraw(&sContext, (const char *)pMsg, -1, 4, 4, 0);
    GrFlush(&sContext);

    nTemp = (Payload[2] << 8) | Payload[3];       // Max current
    sprintf(pMsg, "Max current %d", nTemp);
    cdcSendDataInBackground((uint8_t*)pMsg, strlen((const char *)pMsg), CDC0_INTFNUM, 1);
    GrStringDraw(&sContext, (const char *)pMsg, -1, 4, 24, 0);

    GrFlush(&sContext);

    return;
}

Only in this function do I see pMsg[] filled with random binary trash and not a nice, printable string.

The stack high-water mark is 272 and the stack is 512, so I'm not blowing the stack.

Does anyone know why this could even be a thing?I use sprintf() in all 7 tasks and I see no errors there.

Any help enormously appreciated!

Ed Averill