This looks like magnetic interference from the bridge. The yaw record in the flight log is clearly inconsistent with the yaw as seen in the video:

Additionally, the IMU record shows a sudden disagreement with the position data:

Positionally:

That clearly shows the uncommanded excursion to the east after passing under the bridge.

A full analysis requires the mobile device DAT file (FLY026.DAT).
How to retrieve a mobile device DAT file: How to retrieve a V3.DAT from the tablet

Additionally, the IMU record shows a sudden disagreement with the position data:

Positionally:

That clearly shows the uncommanded excursion to the east after passing under the bridge.

A full analysis requires the mobile device DAT file (FLY026.DAT).
How to retrieve a mobile device DAT file: How to retrieve a V3.DAT from the tablet