True I neglected to remove the global header declaration. My preference was to allocate the header within the function that would utilize it, rather than have one globally reused. That's my OCD kicking in -- disliking data structures that lay around and run the risk of getting corrupted if the radio functions screw up. I know there will be an intact, clean header structure each time the radio gets it.
I hoped to clear up the sporadic malformed packets with huge hop counts or other bogus data, assuming it was data corruption of the global structure. But they still show up from time to time.
That's surprising since the nRF24L01 is supposed to be managing the end-to-end data transfers to avoid corruption in-transit.