pg_listener entries deleted under heavy NOTIFY load only on Windows

Under a heavy load of NOTIFY events, entries in the pg_listener table
for some events are deleted, effectively acting as though UNLISTEN were
called.

I have only been able to make this occur on a PostgreSQL server running
on Windows. I cannot reproduce under Linux.
PostgreSQL version: 8.3.4
Operating System: Windows XP

I have provided some shell script that can reproduce the problem. It
helps to use three psql sessions.

First start a session that listens for two events ("first" and
"second"), then periodically polls for notifications:
check_for_events | psql -h windows_server -U postgres postgres

Second, start an interactive session and execute the command "SELECT *
from pg_listener". You should see the events "first" and "second" listed.

Third, start a session to do repeated notification. The script produces
"NOTIFY first" and "NOTIFY second" in separate transactions repeatedly.
generate_events | psql -h windows_server -U postgres postgres

Continue to check the pg_listener table in the interactive session.
Very quickly one of the two events will disappear from the table.

Strangely, when I execute the same scripts against a database server on
a CentOS Linux system, this problem does not occur.