Unusual behavior for "datomic.tx" as a tempid

Client API
1

Is it a bug that the “datomic.tx” tempid is nil when the transaction id is only in the V position?

(d/transact conn {:tx-data [{:db/id "temptoken"
                                                  :db/ident :delete/me
                                                  :st.oauth.token/updated-by "datomic.tx"}]})

outputs:

{:db-before #datomic.core.db.Db{:id "stt", :basisT 47, :indexBasisT 0, :index-root-id nil, :asOfT nil, :sinceT nil, :raw nil},
 :db-after #datomic.core.db.Db{:id "stt", :basisT 48, :indexBasisT 0, :index-root-id nil, :asOfT nil, :sinceT nil, :raw nil},
 :tx-data
 [#datom[13194139533360 50 #inst "2023-10-19T19:09:00.794-00:00" 13194139533360 true] #datom[79164837212475 183 13194139533360 13194139533360 true] #datom[79164837212475 183 13194139533359 13194139533360 false]],
 :tempids {"temptoken" 79164837212475, "datomic.tx" nil}}

In other situations (notably, augmenting the tx entity with additional attrs) I find “datomic.tx” correctly identified in the tempids data structure.