array type variables in group_bys aren't carried through to the cube tibble

[jonkeane]

ds %>% group_by(cat, cat) %>% summarise(count = n())

Works and the categorical dimensions are preserved in the tibble format of the CrunchCube, however if there is a multiple response or categorical array in the group_by those aren't maintained:

ds %>% group_by(mr, mr) %>% summarise(count = n())