According to their ELOs, and accounting for the fact that Pragg was playing black, this would be predicted to be a 4% occurrence (~30% odds of draw). So, yes, unexpected, but not exactly stunning given that this is one game out of 240 in the round-robin prelims of the tournament.
Another factor is that Carlsen had Covid is still suffering the effects--in fact he has already lost to another player with a rating lower that Pragg's (Hansen) as well as a 20 year old (Esipenko).