Why is AD8041 as an unloaded buffer showing an offset?

I am using an AD8041 opamp for my project.

Initially I tried using it as an unloaded buffer.The schematic is as shown:

The waveforms VG1 and VF1 as obtained on an oscilloscope are shown below:

Waveform VG1:

Waveform VF1:

As can be seen,the output of the buffer shows an offset.Why is this happening?How can it be corrected?I tried using a different AD8041 and it also showed the same behaviour.