2487853 - DBCLONE failed due to different number of rows copied to shadow system compared with the number in source system

During an upgrade using the SUM tool with DMO, it stops in phase MAIN_SHDCRE/SUBMOD_SHDDBCLONE/DBCLONE with following error:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ CLONING ERRORS and RETURN CODE in DBCLONE07.NQ1~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3 ETGCLN DELETE FROM DDSTORAGE WHERE DBSYSABBR = 'ORA' AND TABNAME = 'DB02_COLL_LOG~' AND INDEXNAME = ' '
3 ETGCLN CREATE UNIQUE INDEX "DB02_COLL_LOG^0" ON "DB02_COLL_LOG~" ("COLL_DATE", "COLL_TIME", "CON_NAME", "SMON_ID") PCTFREE 10 INITRANS 002
TABLESPACE PSAPSR3 STORAGE (INITIAL 0000000016 K NEXT 0000000040 K MINEXTENTS 0000000001 MAXEXTENTS UNLIMITED PCTINCREASE 0000 FREELISTS 001)
3 ETGCLN DELETE FROM DDSTORAGE WHERE DBSYSABBR = 'ORA' AND TABNAME = 'DB02_COLL_LOG~' AND INDEXNAME = '0'
3 ETGCLN insert /*+APPEND */ into "DB02_COLL_LOG~" ( "COLL_DATE", "COLL_TIME", "CON_NAME", "SMON_ID", "SMON_NAME", "MONIFILL", "RCODE", "UPLOAD", "DURATION" )
select /*+PARALLEL( DB02_COLL_LOG )*/ "COLL_DATE", "COLL_TIME", "CON_NAME", "SMON_ID", "SMON_NAME", "MONIFILL", "RCODE", "UPLOAD", "DURATION" from "DB02_COLL_LOG"
3 ETGCLN Number of original rows: 11796. Number of copied rows: 11721. 1EETGCLN Number of copied rows 11721 is smaller than expected 11796.
1EETGCLN DB02_COLL_LOG 1EETGCLN Error copying table data
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ CLONING ERRORS and RETURN CODE in DBCLONE07.NQ1~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Update of Netweaver based ABAP system

Database is Oracle

DBCLONE, Number of original rows, is smaller than expected, Error copying table data , KBA , BC-UPG-TLS-TLA , Upgrade tools for ABAP , Problem