Campaign Planned Start/End Date is not editable

Hello Experts,

I have created a marketing campaign in CRM 700 EHP2 system with basic details like: Description, type but without maintaining Planned start/end date.

I maintained the planning data also. But, when I open the same campaign later, I cannot edit the planned start/end date. There are no error mesage that Date is mandatory  while maintaining the planning data.

Problem:

Is it the expected behaviour in marketing campaign with planning? Should Planned start/end date needs to be mandatory for a campaign?

Observed that simple campaign can be edit to maintain the planning date entries.

Thanks in advance,

Soumya