Too long auto takeof

Hello!
I’ve got undesired plane behaviour during auto-takeoff - target takeoff altitude was 50m, plane reached 49.9888m (baro) and then flew 45sec on altitude 49-49.5m before it hit 50m level and takoff was completed.
Here is log https://plot.dron.ee/RGhr
I made 5 flights and only once saw such behaviour

Thanks