diff --git a/saqc/flagger/flags.py b/saqc/flagger/flags.py
index 6f4caf4f9a22017373793d82eb6c1a700c1cbe81..62d8d329207728113e85533babb55654b5ab33e9 100644
--- a/saqc/flagger/flags.py
+++ b/saqc/flagger/flags.py
@@ -405,7 +405,9 @@ def mergeHistoryByFunc(flags: Flags, field, source, merge_func, merge_func_kws,
     target_history = flags.history[field]
     source_history = flags.history[source]
     new_target_history = History()
-    for k in target_history.columns:
+    import pdb
+    pdb.set_trace()
+    for k in target_history.hist.columns:
         col_args_h = dict(source_col=source_history.hist[k])
         col_args_m = dict(source_col=source_history.mask[k])
         col_args_h.update(merge_func_kws)
diff --git a/test/funcs/test_harm_funcs.py b/test/funcs/test_harm_funcs.py
index 41408611f26e7b85b12b801fb59511ef145132f1..d0e72553fd130392c1a2e0278cf5697aa657192e 100644
--- a/test/funcs/test_harm_funcs.py
+++ b/test/funcs/test_harm_funcs.py
@@ -54,7 +54,9 @@ def test_harmSingleVarIntermediateFlagging(data, flagger, reshaper):
     field = data.columns[0]
     data, flagger = linear(data, "data", flagger, freq)
     # flag something bad
-    flagger = flagger.setFlags("data", loc=data[field].index[3:4])
+    f_ser = pd.Series(data=[-np.inf] * len(data[field]), index=data[field].index)
+    f_ser[3:4] = BAD
+    flagger[field] = f_ser
     data, flagger = mapToOriginal(data, "data", flagger, method="inverse_" + reshaper)
     d = data[field]
     if reshaper == "nagg":