you should find the cause of the dropped block and fix it. That is typically caused by an infrequent but expensive computation, for instance a large block of audio data processed at once, a large message parsed occasionally, an unusually large number of messages fired/processed in the same audio block. In your case it may well be this last one, and it only happens for certain distances perhaps?
When a dropout occurs, all the outputs send out zeros.
I seem to remember that the sensor detects objects not just in front of it but also at an angle of about 15 degrees.