view on system tables upgrade?

I've moved from 7.1.2 to 7.2.1 and now
a view does no longer work as intended

create view pgsql_usertables as
select
upper(u.usename) AS TBL_OWNER, upper(t.typname) AS TBL_NAME,
upper(a.attname) AS COL_NAME, a.atttypid AS COL_TYPE,
int4larger(a.attlen, a.atttypmod - 4) AS COL_LENGTH,
CASE WHEN a.attnotnull=true THEN 0 ELSE 1 END AS COL_NULL, a.attnum AS COL_SEQ,
CASE WHEN EXISTS(SELECT adsrc FROM pg_attrdef d
WHERE d.adrelid = a.attrelid and d.adnum = a.attnum) THEN
1
ELSE
0
END AS COL_DEFAULT
from pg_user u, pg_type t, pg_attribute a, pg_type n
where u.usesysid = t.typowner
and t.typrelid = a.attrelid and t.typtype = 'c' and not (t.typname ~* 'pg_')
and n.typelem = a.atttypid
and substr(n.typname, 1, 1) = '_'
and a.attnum > 0 ;

CREATE TABLE catsource
(sid INTEGER NOT NULL,
name VARCHAR(64) NOT NULL,
entrancetime DATETIME NOT NULL
) ;

select col_type,col_length,col_null,col_seq,col_name,col_default
from pgsql_usertables where tbl_name='CATSOURCE' order by col_seq ;

retrieves
col_type | col_length | col_null | col_seq | col_name | col_default
----------+------------+----------+---------+----------+-------------
23 | 4 | 0 | 1 | SID | 0
1043 | 64 | 0 | 2 | NAME | 0
(2 rows)

All columns of type timestamp have disappeared.
Can somebody please give me a hint what happened.

Regards, Christoph