Seeing Diana Rigg and Rebecca Stirling acting their chops off against one another was one of the best parts for me. I've loved those two in anything I've seen them in, to see them together... marvellous.
I'm glad someone else mentioned this, because it seemed to me a wonderful bit of casting - to have mother and daughter play ... mother and daughter!
No, this wasn't good.
As has been said to others, please take the time to explain why you feel this way. As you've seen, a simple all-too-brief comment like this can cause more grief than we need.