REGEXP_COUNT Strange behavior or bug

Dear colleagues,
  Can please anyone confirm that there are a bug and provide the reference to MetaLink or explain such REGEXP_COUNT() function behavior ?

SQL> select * from v$version;
 
BANNER
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Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
PL/SQL Release 11.2.0.3.0 - Production
CORE 11.2.0.3.0 Production
TNS for IBM/AIX RISC System/6000: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production
 
SQL> select regexp_count(chr(10)||chr(10)||chr(10)||chr(10)||chr(10)||'A', '^') start_count from dual;
 
START_COUNT
-----------
          6
 
SQL> select regexp_count(chr(10)||'a'||chr(10)||chr(10)||chr(10)||chr(10)||'A', '^') start_count from dual;
 
START_COUNT
-----------
          2
 
SQL> select regexp_count('a'||chr(10)||chr(10)||chr(10)||chr(10)||'A', '^') start_count from dual;