The very first example, which is held up as an error, is actually arguably correct. If you asked a human (me) how many bananas were purchased, they clearly purchased one banana.

Yes the banana weighs 0.4 pounds. But the question was not to return the weight or the quantity, the question was to return the quantity.

It seems like more instructions are needed in the prompt that the author is not even aware of.

A very common peeled banana weight is 100g (“metric banana”). This is convenient for calorie counting. 0.4lbs for a single banana as the peeled weight is probably around 125g.

https://www.reddit.com/r/dataisbeautiful/comments/bs741l/oc_...

Or one batch of bananas, weighing 0.4 pounds. The number of bananas is not specified in the receipt, and I would not expect the model to estimate it.