Segger J-link fails to reset nrf52840 rev C

This one is weird. On a new board with a Rev C '840, when trying to reset the processor using 'nrfjprog --program nuttx.hex --sectorerase --erase', a Decawave DW1000 connected to the '840 via SPI can't synchronize it's clock. If I power cycle the board, then everything including the DW1000 comes up without a problem. In both cases, we drive the DW1000's reset line low to reset its state.

The same design on an earlier Rev B '840 works either way I 'reset' it.

I'm at a loss to explain how a JTAG/SWD reset of the '840 would impact the ability of the DW1000 to come out of reset and synchronize its clock. I haven't a clue as to whether this is a Nordic, Decawave, Segger or my issue. I'm open to ideas.