Tbh they look like compression lows to me - sudden drops on the graph can indicate lows with bounce back to mid range - where have your sited the sensor ? I put mine onto the bingo wing bit on the back of my arm and rarely get compressions on this area.
Also go by how you feel upon waking, if you feel like you had disturbed sleep or were out partying till the early hours this can indicate a hypo, it's difficult to do a meter test during the night, so getting a sense of things upon waking can help gauge it too.
If the alarm is causing disturbance and your confident that hypos aren't an issue during the night then change the alarm range or tone.