On klog:4231, S2 signal is different from others. We guess that this difference was caused by the reflector surface difference . The pair of sensor head and reflector surface is shown in attached file.
So, we change the pair of sensor. Green is correct S2 pair (S2 and +X surface). Red is correct S3 pair (S3 and -Z surface ). Purple is S3 and +X surface which is we thought bad surface. 
Even we change surface pair, S3 signal was not changed. So We guess S2 sensor head has some problem.