diff --git a/pyuvdata/uvdata/tests/test_uvdata.py b/pyuvdata/uvdata/tests/test_uvdata.py
index fa6106b8d3..a357cf821e 100644
--- a/pyuvdata/uvdata/tests/test_uvdata.py
+++ b/pyuvdata/uvdata/tests/test_uvdata.py
@@ -12712,13 +12712,14 @@ def test_antpair2ind_not_rect_not_ordered(hera_uvh5):
 
 def test_antpair2ind_unordered_both_exist(hera_uvh5):
     # Make a new object that has conjugated baselines in it as well.
+    hera_uvh5.set_rectangularity()
     hera_uvh5.conjugate_bls("ant1<ant2")
     full = hera_uvh5.copy()
-    full.conjugate_bls("ant2<ant1")
-    full.fast_concat(hera_uvh5, axis="blt")
 
-    print(full.get_antpairs())
-    print(hera_uvh5.get_antpairs())
+    full.conjugate_bls("ant2<ant1")
+    full.fast_concat(hera_uvh5, axis="blt", inplace=True)
+    full.select(bls=[(0, 1), (1, 0)], inplace=True)
+    full.reorder_blts(order="time", minor_order="baseline")
     inds_ordered = full.antpair2ind((0, 1), ordered=True)
     inds_unordered = full.antpair2ind((0, 1), ordered=False)
 
diff --git a/pyuvdata/uvdata/uvdata.py b/pyuvdata/uvdata/uvdata.py
index 2999d07e72..8444d1283d 100644
--- a/pyuvdata/uvdata/uvdata.py
+++ b/pyuvdata/uvdata/uvdata.py
@@ -4030,7 +4030,7 @@ def get_baseline_nums(self):
             Array of unique baselines with data associated with them.
         """
         if self.blts_are_rectangular:
-            if self.blt_order == ("baseline", "time"):
+            if self.time_axis_faster_than_bls:
                 return self.baseline_array[:: self.Ntimes]
             else:
                 return self.baseline_array[: self.Nbls]
@@ -7540,6 +7540,8 @@ def fast_concat(
         if this.filename is not None:
             this._filename.form = len(this.filename)
 
+        this.set_rectangularity(force=True)
+
         # Check final object is self-consistent
         if run_check:
             this.check(