[CMT2][BUG] Migrate from urowid to varchar, the value is error

1 Add one table
CREATE TABLE "TEST"."UROWID_TYPE"
( "ID" NUMBER(*,0),
"UROWIDCOL" UROWID (4000)
) PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 NOCOMPRESS LOGGING
STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "USERS" ;
2 Add the data as attachment.
3 Do migration

Actual result
The data is error