Cron for sysstat reports error of /usr/lib64/sa/sa2.

Issue

• Cron for sysstat, which is run every 23:53, sometimes reports following error by e-mail intended for root. Either 'Error 1' or 'Error 2' is reported.
• Error 1

Subject: Cron <root@jseisrefdbsv02> /usr/lib64/sa/sa2 -A

(Body)
mv: `sa20' and `201307/sa20' are the same file

• Error 2

Subject: Cron <root@hostname> /usr/lib64/sa/sa2 -A

(Body)
date: sa12: No such file or directory
/usr/lib64/sa/sa2: line 32: [: : integer expression expected

• Value of 'HISTORY' is changed to '30'.
• sa1 runs every minute.