Issue:

Currently the main account that is selected in the offset account defaults the dimensions from the main account that is selected in the account, which is quite cumbersome for the user to know which dimensions are used for the offset account until the journal is posted and he/she can view it in the Voucher details. Even, the warning message that says "Dimension combination is incorrect for the offset account"

Solution:

Currently from the link Default financial dimensions on financial journals - Finance | Dynamics 365 | Microsoft Learn we know that the validation on the dimensions happens when the journal is posted and until then the user is unaware of the financial dimensions that will be populated against the offset account. It is convenient and less cumbersome for the user to have the default dimension for the offset account from the main account legal entity overrides and not from the account. To avoid any confusion and inappropriate warning messages.

Why should the validation happen when the journal is posted ?

Why can't we default it as usual as we do for the account ? - If this has been happening other way around for this long I assume there must be some reason for it ? Could you please provide more insights on this ? and consider the solution as it is a high priority for us.