Laser scan wont update although decay time set to zero- gmapping

Hi, I am having this issue when playing the bag file [dropbox link](https://www.dropbox.com/s/jnbfuqilish1lem/test_28jan.bag?dl=0). I recorded this bag file with /scan and /tf on a p3dx which has a UHG-08lx laser sensor. The gmapping works fine. But the laser scans wont update and accumulate into the map, although the decay time is set to zero. This problem is for every bag file that I record. See attached [screenshot](https://www.dropbox.com/s/h34dhmcu55er0av/rviz_screenshot_2015_01_28-22_05_30.png?dl=0) Can someone suggest as to why this is happening and how can I resolve it. Thanks