Extracting all the lines from the raw data where the difference between two readings is more than 1μV confirms that each one happens when there's a drift compensation as the time delta between the two readings is always around 20 seconds longer than expected.
VDelta 1.1e-06
2020-02-16 16:29:43,24.17,40.53,983.69,+1.0183882
2020-02-16 16:30:11,24.17,40.53,983.69,+1.0183871
VDelta 1.6e-06
2020-02-16 21:59:54,24.00,40.58,983.98,+1.0183910
2020-02-16 22:00:22,23.99,40.61,984.00,+1.0183926
VDelta 1.3e-06
2020-02-16 23:44:58,23.92,39.94,983.66,+1.0183939
2020-02-16 23:45:25,23.92,39.94,983.66,+1.0183952
VDelta 1.6e-06
2020-02-17 02:45:04,23.82,38.76,982.96,+1.0183990
2020-02-17 02:45:32,23.82,38.76,982.96,+1.0184006
VDelta 1.4e-06
2020-02-17 06:00:05,23.76,38.15,984.77,+1.0184018
2020-02-17 06:00:32,23.76,38.15,984.77,+1.0184032
VDelta 1.2e-06
2020-02-17 07:15:07,24.00,38.99,985.61,+1.0183979
2020-02-17 07:15:35,24.00,38.99,985.61,+1.0183967
VDelta 1.2e-06
2020-02-17 12:15:16,23.89,37.10,988.15,+1.0183956
2020-02-17 12:15:44,23.89,37.13,988.18,+1.0183944
VDelta 1.1e-06
2020-02-17 13:30:11,23.86,37.15,988.32,+1.0183945
2020-02-17 13:30:39,23.87,37.13,988.18,+1.0183956
I'm sure I remember reading something about a bug with Solartron 70x1 meters and drift compensation, but I can't for the life of me find the thread.