Same KV operations fail on R1 vs R3

[MauriceVanVeen]

If replicas is set to 1, this test fails:

--- a/server/jetstream_cluster_4_test.go
+++ b/server/jetstream_cluster_4_test.go
@@ -3048,7 +3048,7 @@ func TestJetStreamClusterKeyValueLastSeqMismatch(t *testing.T) {

        kv, err := js.CreateKeyValue(&nats.KeyValueConfig{
                Bucket:   "mismatch",
-               Replicas: 3,
+               Replicas: 1,
        })
        require_NoError(t, err)

1 lastseq 2
    jetstream_cluster_4_test.go:3070: require error, but got none
--- FAIL: TestJetStreamClusterKeyValueLastSeqMismatch (0.52s)

Is that expected? Seems unexpected that clustered-ness would affect the outcome of the KV operations.

Originally posted by @cbrewster in #5821 (comment)