Translation:She often talks to us about it because she loves it.
I think the main problem with that translation here is that "en" (or "y") can't be used to replace a person, so we know from the first part of the sentence that we are talking about an "it", not a "he" or "she". And I guess it would be weird for the " en " and " l' " to not refer to the same thing.
In the "Type what you hear" exercise, "Elles nous en parlent souvent parce qu'elles l'adorent." is rejected.
I don't think it should be. Am I right?
However, "Elles nous en parlent souvent parce qu'elle l'adore." is accepted! Is there really an audible difference?