Upgraded firmware to 5.07, software to 6.05, recalibrated voltage and all is well with the logger. Sessions are once again correctly marked.

If nothing else, it's interesting how each battery has its own very distinct signature.

Flight 1 was on a TP3850-10SX pack. Flight 2 – 4 were on TP5000-10SX’s

Flight 2 – 78 cycle pack (seems to be the strongest pack)
Flight 3 – 55 cycles
Flight 4 – 17 cycles