BUG #4674: Unable to open lob

The following bug has been logged online:

Bug reference: 4674
Logged by: Yuichi Tanaka
Email address: yuichi_tanaka(at)cybozu(dot)co(dot)jp
PostgreSQL version: 8.3.6
Operating system: Linux
Description: Unable to open lob
Details:

I wrote the code like below:

// open lob
if( (pgsql_lofd1 = lo_open(pgsql, oid, pgsql_mode)) == -1 ) {
printf("error: first lo_open\n");
}

// send query asynchronously
PQsendQuery(pgsql, "INSERT INTO bar (name) VALUES ('aaa');" );

// open lob
if( (pgsql_lofd2 = lo_open(pgsql, oid+1, pgsql_mode)) == -1 ) {
printf("error: second lo_open\n");
}

This program displays "error: second lo_open".
Is this a bug or correct behavior?