Dimensions equal in sequence and export, but exported files still bigger.

This is really bugging me out, cannot for the life of me see what I'm doing wrong.

HAve a file with a vertical file dimension of 408x768

In sequence settings it is correct.

In export it is using the same dimensions...

but I am getting a taller/longer exported file.

Attach screenshots... please, I cannot for the life of me see why or how this is happening.

Thanks all