Went through the comments here and there and one thing to note is that there was a question about who do you think should have won instead. This is a good question because it is possible that all submissions were like this or there were ones that looked just worse. It would be quite useful to know who came close as well in this case. If you knew which submissions were good you could have a process to revoke the prize and give it to someone else in case of fraud or negligence or similar.
Having said that it is also possible that the mistakes and claims were a human error, sure a lot gets ai generated these days but there is a chance in which case the accusation does not look so severe anymore.
Assuming this description is accurate, if they were all like this then none of them should have won. They should have all been disqualified and the organizers should have looked at themselves in a mirror for a long time.