kWh meter running backwards -- very fast

My video voice is in Dutch, but a translation is provided in this text box.

KWh meter running backwards

0:06 Here we have a Landis & Gyr check meter which is connected to a panel and it is going in reverse.
0:12 Hazelmeijer fuse box.
25 Ampère on one circuit and 20 Amps on the other.
0:20 This is on a power factor circuit.
0:25 The meter runs occasionally forwards and backwards.
0:35 It depends how the power factor is.
0:50 The current varies between 25 and 12 Ampères.
0:55 The meter goes sometimes forward with leading PF.
1:14 The brake magnet works well on the meter.
1:24 The meter is from Landis & Gyr type CL2 with horizontal number wheels with digits next to each other. Interesting design with all aluminium gears and intermediate gears.
2:07 The fuse is 25 Amps with a yellow dot , and the other, (just removing the shadow) is blue 20 Amps.
2:18 Control circuit box.