This is probably due to the frame rate from preset bug fix I mentioned here:
Look at your two output files and compare their frame rate and resolution.
Also, you are using VAAPI, which is going to be quite dependent on whatever ffmpeg and the driver decides to do with qscale. In particular, FFmpeg dropped or broke support for qscale in VAAPI when we upgraded to v4.2. We now use vglobal_quality with a different numeric range. You will need to adjust the preset accordingly.