Is the mother of the groom expected to bring a gift to every bridal shower?

It's rather unusual for there to be more than one bridal shower, but
if there is, and the future mother-in-law is invited to each one, she
should only be expected to bring one gift, one time.

Kriswrite

I quite agree, though I could imagine that a bride might have too many
friends or friends from different aspects of her life that she wanted
to invite as separate groups.
Her future mother-in-law would be invited to all the showers to
introduce the friends of the bride to her, not because she should join
in the shower of gifts each time.