She did at least once mention her to a Foreign Ambassador, defending her mother's reputation. Statements like "never talked" have to be treated with extreme caution. Just because the official records might not mention that Elizabeth spoke of her mother, does not mean that she never spoke of her.  In 1575 she had a ring made which contained a picture of both her and her mother in it. She must have mentioned her mother to have had this made.

You can see the remarkable  ring  at the Tudor History site