My speculation about the reasons for cruises disappearing from the online calendar might not be quite right - the SofA has a trip called "Scandinavian Explorer" (renamed from "Baltic Capitals") on June 5 2023, and the SofD has "Contrasts of Scandinavia" on May 21, and both of these are still shown on the calendar. They both visit Helsinki, Kotka and Tallinn, as did the cruises which have been removed from the online calendars. If there were deemed to be problems with cruises visiting the Baltic, these would also have been subject to change, I would think.
Ivycottage, if you could let us know which cruise has been cancelled, it would be very helpful. And if Saga ever gives you a reason for the cancellation, that would be even more helpful to know! I just hope it's nothing to do with debts, inflation, rising interest rates and falling share price ...