Slash has a little better error handling:
resolving updateGQLSchema failed because input:601: Type Mutation; Field editUser; body template inside @custom directive could not be parsed.
input:607: Type Mutation; Field removeUser; body template inside @custom directive could not be parsed.
This is interesting. Not sure why it would allow your createUser to go through seemingly without error, but error parsing your editUser and removeUser.
This was a long shot, but I actually resolved out why. Not that I think it is correct, but that it is a Dgraph bug/restriction.
Your body for editUser and removeUser both contain this snippet:
auth0ID: $auth0ID
I was able to receive a successful parse by using instead:
authID: $auth0ID
I believe that numbers are allowable in property names in JSON.
The problem was identified here:
But was should now be resolved as also noted on that same thread:
It was committed here:
https://github.com/dgraph-io/dgraph/commit/02820c8921a3a954880505c18cc5f0c875168b9a
And can be seen inside version 20.07.1-rc1 here:
Which version are you running?