[issue] wal_buffers_full increases depending on the values of wal_buffers and wal-segsize

If the wal segment size is larger than the wal_buffers parameter value, the
value of the wal_buffers_full column of pg_stat_wal increases after
database shutdown and startup.

pg_controldata | grep "Bytes per WAL segment"
Bytes per WAL segment: 1073741824

wal_buffers = 16MB

---- DB shutdown and restart
postgres=# select * from pg_stat_wal;
wal_records | wal_fpi | wal_bytes | wal_buffers_full | wal_write |
wal_sync | wal_write_time | wal_sync_time | stats_reset
-------------+---------+-----------+------------------+-----------+----------+----------------+---------------+-------------------------------
6165 | 462 | 14071380 | * 126070* | 126115 |
40 | 0 | 0 | 2022-04-25
14:28:04.746772+09
(1 row)

If wal_buffers size and wal_segment size are the same, wal_buffers_full
column does not increase.

pg_controldata | grep "Bytes per WAL segment"
Bytes per WAL segment: 16777216

wal_buffers = 16MB

postgres=# select * from pg_stat_wal;
wal_records | wal_fpi | wal_bytes | wal_buffers_full | wal_write |
wal_sync | wal_write_time | wal_sync_time | stats_reset
-------------+---------+-----------+------------------+-----------+----------+----------------+---------------+-------------------------------
6161 | 461 | 14062929 | * 0 *| 39 |
36 | 0 | 0 | 2022-04-25
12:13:35.838092+09
(1 row)

Is this a bug?

The postgreSQL version currently in use is 14.2, and the database was
restarted without performing DML and DDL.

I wonder if it doesn't matter if the values of wal_buffers and wal-segsize
are different.