Why doesn't a Gantt Timescale in OPC reflect the Settings?

In OPC Schedule we are not able to print a Gantt chart showing activities, because the Timescale in the Gantt chart doesn't reflect the Time Interval chosen under Settings.
We have a Data Date of 24-Nov-2022 and Timescale Settings as follows:
Timescale: Year Month
Use rolling dates
Start: Data Date -1 Month
End: Data Date +23 Months

But the Gantt Timescale starts at -27 Months and ends at -11 Months, and no Bars are shown in the Gantt chart at all.

Any ideas of how to resolve this issue?

Br,

Finn