Hello,
I am facing same problem at the moment, when I try to submit any score (currently trying with Cinebench R20). The error shows sometimes when I use the option to prepopulate fields by previous submission (when clicking in the relevant submission), and always when clicking the "submit benchmark results" button
Around 12h ago it started happening to me. Seems weird, because same day in the morning I was able to submit a score with no problems.