Though the Sony Xperia support team has already been notified, but they seem to have yet figure out a fix to this problem. Even though there are users who reported that upgrading the firmware to the latest ” 9.0.1.D.0.10 ” version helps, but there are also some who have experienced the problem again after the upgrade.
So for the time being stay tune for more updates from us!
Source : Xperia Blog