ofz#6999 improve fix

Change-Id: Ib95ac17011ca2cc98a4d2288cb5879e163482932
Reviewed-on: https://gerrit.libreoffice.org/51573Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sw/source/filter/ww8/ww8par4.cxx

@@ -477,8 +477,8 @@ void SwWW8ImplReader::Read_CRevisionMark(RedlineType_t eType,
     const sal_uInt8* pSprmCDttmRMark;
     if( nsRedlineType_t::REDLINE_FORMAT == eType )
     {
-        pSprmCIbstRMark = nLen >= 2 ? pData+1 : nullptr;
-        pSprmCDttmRMark = nLen >= 5 ? pData+3 : nullptr;
+        pSprmCIbstRMark = nLen >= 3 ? pData+1 : nullptr;
+        pSprmCDttmRMark = nLen >= 7 ? pData+3 : nullptr;
     }
     else
     {