Prevent buffer-face-mode affecting modus-themes-reset

Having modus-themes-reset inherit from default has the effect it being affected by buffer-face-mode. In the case of Avy, in a mixed pitched buffer (e.g. an Org buffer with blocks), when the line height (physical pixels) of variable-pitch is higher than that of default (I presume the other way around is uncommon), this pushes the hints at the bottom of the window out of view. Notice how the same buffer in the window on the right is "longer":

Inheriting from fixed-pitch fixes this (the highest face on a line wins). This works for me but maybe I'm making too much assumptions?

EDIT: Maybe modus-themes-reset is too aggressive and should just clear inherit and not touch the font family?