diff --git a/pygsti/models/cloudnoisemodel.py b/pygsti/models/cloudnoisemodel.py
index e6aefe8a7..74ace9bf9 100644
--- a/pygsti/models/cloudnoisemodel.py
+++ b/pygsti/models/cloudnoisemodel.py
@@ -708,6 +708,7 @@ def _layer_component_cloudnoises(self, model, complbl_list, cache):
 
         else:
             for complbl in complbl_list:
+                complbl = complbl.strip_args() if complbl.collect_args() else complbl
                 if complbl in cache:
                     ret.append(cache[complbl])  # caches['cloudnoise-layers'] would hold "simplified" instrument members
                 elif complbl in model.operation_blks['cloudnoise']:
diff --git a/pygsti/models/modelnoise.py b/pygsti/models/modelnoise.py
index 1f5ed5158..f0e58c989 100644
--- a/pygsti/models/modelnoise.py
+++ b/pygsti/models/modelnoise.py
@@ -537,7 +537,7 @@ def apply_errormap_stencil(self, stencil, evotype, state_space, target_labels=No
                 # `None` in list signals a non-present direction => skip these terms
                 sslbls_list = list(filter(lambda x: x is not None, sslbls_list))
             for sslbls in sslbls_list:
-                op_to_embed = local_errormap if (sslbls is None or state_space.is_entire_space(sslbls)) \
+                op_to_embed = local_errormap if (sslbls is None) \
                     else _op.EmbeddedOp(state_space, sslbls, local_errormap)
                 embedded_errmaps.append(op_to_embed.copy() if copy else op_to_embed)
 
diff --git a/pygsti/objectivefns/objectivefns.py b/pygsti/objectivefns/objectivefns.py
index e97c7829d..b125d7727 100644
--- a/pygsti/objectivefns/objectivefns.py
+++ b/pygsti/objectivefns/objectivefns.py
@@ -4716,6 +4716,7 @@ def _hessian_from_block(self, hprobs, dprobs12, probs, element_slice, counts, to
             firsts, indicesWithOmitted = zip(*([(iel - element_slice.start, ic) for (iel, ic)
                                                 in zip(self.firsts, self.indicesOfCircuitsWithOmittedData)
                                                 if element_slice.start <= iel < element_slice.stop]))
+            firsts = list(firsts)
 
             #Allocate these above?  Need to know block sizes of dprobs12 & hprobs...
             dprobs12_omitted_rowsum = _np.empty((len(firsts),) + dprobs12.shape[1:], 'd')