First, here's the witp staff HI tracking, the green curve goes with the axis on the right and shows the change in HI. There are occasional downward spikes of great magnitude. (Note the spikes are more similar in magnitude than they appear on the graph; the quasi-log scale used by Witp Staff makes (for example) a +100 to -4900 spike look far bigger than a -1100 to -6100 spike even thought the magnitude is the same.)
EDIT: I just noticed this turn does cross a month boundary. I vaguely recall some kind of post that the pilot training used something on a monthly basis. Was that HI, and if so what order of magnitude does training consume? A number of the spikes could be on month end boundaries so perhaps that's part of the explanation, but not all, there's at least one that is clearly not. But i would have to investigate to make sure I didn't do a ton on factory expansion or conversion or whatever on that turn.


