PJC_COST_DIST_LINES_ALL, Why is the the ACCT_EVENT_ID not populated?

Summary:

Why is the field ACCT_EVENT_ID in some cases not populated in the PJC_COST_DIST_LINE_ALL table, even if the cost is fully accounted?

We need to verify whether all costs in Oracle Projects have been fully accounted.

We have encountered an issue in linking the costs (table: PJC_COST_DIST_LINE_ALL) (exists imported costs from modules like PO, Inventory) to the XLA_AE_HEADERS table using the table XLA_DISTRIBUTION_LINKS .

Is there a way for all costs (also to oracle project imported costs) in the PJC_COST_DIST_LINE_ALL to link to XLA_AE_HEADEARS to check if the cost is accounted?