Overlapping sleep phases


I downloaded the sleep as android data (sleep-export.csv) and noticed that sometimes different sleep phases overlap.
E.g. Light start is at 3 AM, then REM Start is at 3:15 AM, then REM End is at 3:25, and then Light End at 3:30 AM.
This is also the case for other sleep phases.

How is this possible? Is this an error or is there another explanation for this?

Hello, could you please share a screenshot of this graph?


I haven’t plotted the data, I noticed this merely by looking at the data. Here is a screenshot of my dataframe, representing this issue. I used a converter to transform the events into a readable format. I already checked whether the issue is due to the converter, however the timestamps align with the original format.