Regression 11gR2 vs 10gR1 ?

Is there a reason why such statement run fine in 10gR1 and not in 11gR2 ?
SQL10gR1> create table TEST (nordvacte number,nordv number,noacteplanif number, rang number,etat char(1),
 timestamp date not null, timecreate date not null);

TABLE CREEE

SQL10gR1> Alter Table TEST
MODIFY(NOACTEPLANIF NUMBER Not NULL)
MODIFY(NORDVACTE NUMBER Not NULL)
MODIFY(ETAT VARCHAR2(1) DEFAULT 'A' NOT NULL)
ADD (NORDVORIGINE NUMBER(10) NULL)
ADD (TIMEREMOVE Date null )
/

TABLE MODIFIEE

SQL11GR2> create table TEST (nordvacte number,nordv number,noacteplanif number, rang number,etat char(1),
 timestamp date not null, timecreate date not null);

TABLE CREEE

SQL11GR2> Alter Table TEST