Does the text contain a vague pronoun reference? The airline lost Eve's baggage when she flew to Montreal with her sister last month.

No.

Explanation:

A pronoun is when you define a person with a word by using their gender, like "he, her, him, she," etc. A vague pronoun reference is still a pronoun because it defines someone but does not specifically give their gender. \

For example: "It was very tired."

Now, look back at the text. The pronouns the author used was "she, her." These definitely let us know that Eve is female and so is not a vague pronoun reference.