[Observium] Billing started giving unrealistic P95s

Probably somewhere between r3465 to r3981 (yes, I know) billing started producing wrong results. now at 4102, the situation remains the same. I do run the discovery script after each update.

Graphs (quick graphs) look fine with real traffic accounted, but the calculated P95 is unrealistically low (something like 1/3 of the real P95, but this ratio is different for each case). Both with single VLAN and multiple VLAN bills. One of the bills (with id=1) works completely fine though.

Any ideas where to look at / what to compare at the working case with the non-working case?

Thanks,

Hynek