I received a short statement from LoTW about FT8 Mode contacts in regard to the uploading to LoTW:
We have been inundated with emails about FT8. We were told that it will be a few weeks before the developers can get LoTW set up to accept FT8.
So please stand by, LoTW are aware that this work needs to be done before FT8 QSOs can be uploaded to the LoTW databse. Thank you for your patience,