It seems to be very hit and miss...
The below is from the machine described in this thread running PostgreSQL 9.4.10:
update 100000
update 120000
update 140000
update 160000
update 180000
Update all
Vacuum
org.postgresql.util.PSQLException: ERROR: unexpected chunk number 2285 (expected 0) for toast value 187504167 in pg_toast_187504156
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2455)
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:2155)
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:288)
at org.postgresql.jdbc.PgStatement.executeInternal(PgStatement.java:430)
at org.postgresql.jdbc.PgStatement.execute(PgStatement.java:356)
at org.postgresql.jdbc.PgPreparedStatement.executeWithFlags(PgPreparedStatement.java:168)
at org.postgresql.jdbc.PgCallableStatement.executeWithFlags(PgCallableStatement.java:78)
at org.postgresql.jdbc.PgPreparedStatement.execute(PgPreparedStatement.java:157)
at Start.execute(Start.java:118)
at Start.main(Start.java:20)
=========================================
New attempt - number 2
Inserting the rows
Executing 0
Executing 40000
Executing 80000
Executing 120000
Executing 160000
Executing 200000