The baseline date is empty disregarding the payment terms is determined already.
SAP S/4HANA Cloud
Reproducing the Issue
How to calculate the payment terms and baseline date in Journal Entry - Post.
If below fields are filled in payload, and meanwhile there is nothing filled about payment terms, the payment terms could be defaulted from master data, but the baseline will be empty.
As if below fields are filled, it implies the Central Finance is used, then it will block the recalculation of the baseline date.
payment terms, Journal Entry - Post, baseline date. , KBA , AC-INT , Accounting Interface , How To