TYPO3 4.7.19 piBase $GLOBALS['BE_USER'] get blank

Question

I have a TYPO3 piBase BE extension. I have debuged the code and I got the following issue: When I have logged into BE with "www", I got value of $GLOBALS['BE_USER']. But when I have logged into BE without "www", I got a blank array in $GLOBALS['BE_USER']->user.

I have tried:

$GLOBALS['BE_USER'] = t3lib_div::makeInstance('t3lib_tsfeBeUserAuth');
$GLOBALS['BE_USER']->start();

But still I got a blank array when login without "www".