Why is the replication delay in pgpool showing a very large number?

To calculate replication delay in pgpool, the value is obtained from the view **pg_stat_replication.replay_lag**. However, sometimes when executing **show pool_nodes**, it displays a significantly larger number. In the **pg_stat_replication** view, the **replay_lag** is represented as values like **00:00:00.778134**. How **repliation_delay** calculated at **pgpool**? I suspect it is converted into microseconds. I am looking for expert opinion.

node_id  |   hostname   | port | status | lb_weight |  role   | select_cnt  | load_balance_node | replication_delay | replication_state | replication_sync_state | last_status_change
---------+--------------+------+--------+-----------+---------+-------------+-------------------+-------------------+-------------------+------------------------+---------------------
 0       | 		db1		| 5678 | up     | 0.200000  | primary | 12401123776 | false             | 0                 |                   |                        | 2023-05-28 00:45:31
 1       | 		db2		| 5678 | up     | 0.200000  | standby | 11909003735 | false             | 0                 | streaming         | async                  | 2023-05-28 00:45:31
 2       | 		db3 	| 5678 | up     | 0.200000  | standby | 11930293446 | true              | 61768             | streaming         | async                  | 2023-05-28 00:45:31
 3       | 		db4 	| 5678 | up     | 0.200000  | standby | 11829890748 | false             | 776136            | streaming         | async                  | 2023-05-28 00:45:31
 4       | 		db5 	| 5678 | up     | 0.200000  | standby | 11898267765 | false             | 124128            | streaming         | async                  | 2023-05-28 00:45:31