Unexpected pulses in the output signal from IR Detector
The datasheet warns in point 9 on the last page:


  There is a possibility that noise on output may be caused by environmental condition (Disturbing light noise, Electromagnetic
  noise, Power supply line noise, etc.) even if there is no input
  transmission signal.


So it sounds like the manufacturer accepts that you may get false positives once in a while.  Other than controlling your environmental conditions and having good power supply bypassing, you're probably going to have to filter out these glitches in software.  You could have a circuit that filtered them based on minimum duration for example, but this so easily done in firmware that it's not worth the cost+area involved in a pure hardware filter.