你这个问题其实大部分都说是可忽略的，因为数据同步压根不是通过archive log list去确认dg是否接收归档，正常同步。 但是说话要讲证据，搜了一下有一篇类似的mos Archive Log List Showing 0 At Standby, But Standby Is Completely In Sync With Primary! (Doc ID 2041137.1)
Oracle Database - Enterprise Edition - Version 12.1.0.2 and later
The ARCHIVE LOG LIST Command showing 0 at standby, but standby is completely in sync with primary

SOLUTION
Do not use ARCHIVE LOG LIST on standby side.

解决方案
不要在备用端使用 ARCHIVE LOG LIST。

使用下面的查询来确定数据库是否同步

Primary: SQL> select thread#, max(sequence#) “Last Primary Seq Generated”
from v$archived_log val, v$database vdb
where val.resetlogs_change# = vdb.resetlogs_change#
group by thread# order by 1;

PhyStdby:SQL> select thread#, max(sequence#) “Last Standby Seq Received”
from v$archived_log val, v$database vdb
where val.resetlogs_change# = vdb.resetlogs_change#
group by thread# order by 1;

PhyStdby:SQL>select thread#, max(sequence#) “Last Standby Seq Applied”
from v$archived_log val, v$database vdb
where val.resetlogs_change# = vdb.resetlogs_change#
and val.applied in (‘YES’,’ IN-MEMORY’)
group by thread# order by 1;