If you read the coverage of the judges jury instruction you will find that he was careful not lead the to any conclusions and it was up to the jury to decide.
The defence acknowledged as did Erin that she lied and gave some plausible reasons for it, they also pointed out there was no stand out motive.
Much of the prosecution evidence and witness was some what circumstantial rather than direct evidence.
The fact that Erin could not say/prove were the mushroom came from and sent people on a wild goose chase looking for possible death cap mushrooms being sold to the public stands out, also quite sure they never established just were/how the mushroom came to be in the meal and that some how she didn't get sick herself.
End of the day jury has find she was guilty beyond reasonable doubt which is quite a high bar, if they have any reasonable doubt they must find her not guilty.
