Boost Converter Inefficiency
I believe those "strange pulses" are actually your 520 kHz switching waveform. Although Diodes Inc. really half-asses their data sheets, it's likely that under light load conditions it will enter discontinuous mode. This is when it's achieved the required output voltage, and further current will put it over the top. Then it stops switching until the voltage droops, and restarts to maintain the output voltage.

Under these light load conditions, the efficiency will be terrible, since the controller and switching currents are higher than the output current. This isn't usually a problem, because the total current in is still fairly small. Have you measured it with a load?