refresh! breaks when passing a block to initialize the connection

Created by: Linuus

When I pass a block to initialize the Faraday object it breaks the refresh! method, even if I only set the default adapter.

 def access_token
   OAuth2::AccessToken.new(client, @token, @opts)
 end

 def client
   OAuth2::Client.new(
     ENV["SOME_APP_ID"],
     ENV["SOME_APP_SECRET"],
     site: ENV["SOME_APP_URL"],
     authorize_url: "login/oauth/authorize",
     token_url: "login/oauth/token"
   )
 end

access_token.refresh! # => Works!

def access_token
   OAuth2::AccessToken.new(client, @token, @opts)
 end

 def client
   OAuth2::Client.new(
     ENV["SOME_APP_ID"],
     ENV["SOME_APP_SECRET"],
     site: ENV["SOME_APP_URL"],
     authorize_url: "login/oauth/authorize",
     token_url: "login/oauth/token"
   ) do |faraday|
    faraday.adapter Faraday.default_adapter
  end
 end

acces_token.refresh! # => undefined method bytesize for Hash

Any idea what's going on here?