Incorrect number of parameters in "role" errors

The following code produces the error:

import Data.Coerce
import Data.Functor.Trans.Tagged

toTT :: Tagged t [a] -> TaggedT t [] a
toTT = coerce

Couldn't match representation of type ‘[a]’
                             with that of ‘Data.Functor.Identity.Identity [a]’
    arising from trying to show that the representations of
      ‘Tagged t [a]’ and
      ‘TaggedT t [] a’ are the same
    Relevant role signatures:
      type role [] representational
      type role Data.Functor.Identity.Identity representational
      type role TaggedT nominal nominal phantom representational nominal
    The data constructor ‘Data.Functor.Identity.Identity’
      of newtype ‘Data.Functor.Identity.Identity’ is not in scope
    Relevant bindings include
      toTT :: Tagged t [a] -> TaggedT t [] a (bound at Main.hs:9:1)
    In the expression: coerce
    In an equation for ‘toTT’: toTT = coerce

First, kudos for correctly identifying the problem: I failed to import the Identity constructor. However, it seems that the report for the roles of the TaggedT type has too many parameters. It is defined in tagged-transformer https://hackage.haskell.org/package/tagged-transformer-0.8/docs/Data-Functor-Trans-Tagged.html as newtype TaggedT s m b = TagT { untagT :: m b }, but is listed with 5 roles.

I did try to move the definition of TaggedT/Tagged into my module so I didn't have to import the library, but when I did the error didn't show up: TaggedT was listed with the expected roles phantom representational nominal.

As a user, it wasn't clear to me why there are 5 roles listed for a type with 3 parameters, and I didn't know which roles I should be looking at to help me debug the coerce error. It's also not clear why using the library vs defining the types locally changed the behavior.