QueryRaw with "IN" a "GROUP" is not unique, low rate

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I have search in issues with keyword "queryRaw", but no similar question is find.
scene
I want to get a RecentContact list from a table of chat record.
The chat bean has fields : sn(as id), targetId, srcId, content, time and ...

for once query, i used raw query:

.getChatBeanDao()
                .queryRaw(" WHERE T.TIME IN" +
                        " (" +
                        " SELECT MAX(TIME)" +
                        " FROM CHAT_BEAN" +
                        " WHERE SRC_ID = " + userId +
                        " GROUP BY TARGET_ID" +
                        " )" +
                        " GROUP BY TIME" //time unit is second, maybe has several in one second
                );

problem
Now i find a result log like this:

17:16:40.303
：ChatBean{sn=1, targetId=213, srcId=321, content='some', time=1580979909}
：ChatBean{sn=2, targetId=213, srcId=321, content='😔', time=1580979934}

It is confused.
When i insert these records in local, and query by the same code, result is unique. Which means i can't reproduce it.
more
nearby the code with problem, another query also is right:

queryBuilder
                .where(
                        ChatBeanDao.Properties.SrcId.eq(myUserId),
                        ChatBeanDao.Properties.TargetId.eq(targetUserId),
                )
                .orderDesc(ChatBeanDao.Properties.Time)
                .limit(1)
                .unique();
// result
17:16:40.455
: last unread is ChatBean{sn=2, targetId=213, srcId=321, content='😔', time=1580979934}

The time only passed 150 milliseconds

Could anyone tell me some ways to solve it ? thank you