diff --git a/pyproject.toml b/pyproject.toml
index 53d7c5deb..416f46762 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "wisdem"
-version = "4.2.5"
+version = "4.2.6"
 description = "Wind-Plant Integrated System Design & Engineering Model"
 readme = "README.md"
 requires-python = ">=3.11"
diff --git a/wisdem/ccblade/ccblade.py b/wisdem/ccblade/ccblade.py
index 6383f5b3e..51c511458 100644
--- a/wisdem/ccblade/ccblade.py
+++ b/wisdem/ccblade/ccblade.py
@@ -102,13 +102,16 @@ def max_eff(self, Re):
         aoa_end = 40
 
         alpha = np.deg2rad(np.linspace(aoa_start, aoa_end, num=201))
-        cl = np.array([self.cl_spline.ev(aoa, Re) for aoa in alpha])
-        cd = np.array([self.cd_spline.ev(aoa, Re) for aoa in alpha])
+        cl = np.array([self.cl_spline.ev(aoa, Re) for aoa in alpha]).flatten()
+        cd = np.array([self.cd_spline.ev(aoa, Re) for aoa in alpha]).flatten()
 
         if np.max(cl) < 1.e-3:  # Cylinder
             alpha_Emax = 0.
             cl_Emax = self.cl_spline.ev(alpha_Emax, Re)
             cd_Emax = self.cd_spline.ev(alpha_Emax, Re)
+            if isinstance(cl_Emax, np.ndarray):
+                cl_Emax = cl_Emax.item()
+                cd_Emax = cd_Emax.item()
             Emax = cl_Emax / cd_Emax
         else:
             Eff = [cli / cdi for cli, cdi, in zip(cl, cd)]
@@ -139,7 +142,7 @@ def awayfromstall(self, Re, margin):
         else:
             alpha = np.deg2rad(np.linspace(aoa_start, aoa_end, num=201))
             cl = [self.cl_spline.ev(aoa, Re) for aoa in alpha]
-            cd = [self.cd_spline.ev(aoa, Re) for aoa in alpha]
+            #cd = [self.cd_spline.ev(aoa, Re) for aoa in alpha]
 
             i_stall = np.argmax(cl)
             alpha_stall = alpha[i_stall]
@@ -147,6 +150,9 @@ def awayfromstall(self, Re, margin):
 
         cl_op = self.cl_spline.ev(alpha_op, Re)
         cd_op = self.cd_spline.ev(alpha_op, Re)
+        if isinstance(cl_op, np.ndarray):
+            cl_op = cl_op.item()
+            cd_op = cd_op.item()
         Eff_op = cl_op / cd_op
 
         # print Emax, np.deg2rad(alpha_Emax), cl_Emax, cd_Emax
@@ -175,11 +181,16 @@ def evaluate(self, alpha, Re, return_cm=False):
         also uses a small amount of smoothing to help remove spurious multiple solutions.
         """
 
-        cl = self.cl_spline.ev(alpha, Re)[0]
-        cd = self.cd_spline.ev(alpha, Re)[0]
-
+        cl = self.cl_spline.ev(alpha, Re)
+        cd = self.cd_spline.ev(alpha, Re)
+        if isinstance(cl, np.ndarray):
+            cl = cl.item()
+            cd = cd.item()
+            
         if self.use_cm and return_cm:
-            cm = self.cm_spline.ev(alpha, Re)[0]
+            cm = self.cm_spline.ev(alpha, Re)
+            if isinstance(cm, np.ndarray):
+                cm = cm.item()
             return cl, cd, cm
         else:
             return cl, cd
diff --git a/wisdem/optimization_drivers/nsga2_driver.py b/wisdem/optimization_drivers/nsga2_driver.py
index 14831253c..c6b9f52f5 100644
--- a/wisdem/optimization_drivers/nsga2_driver.py
+++ b/wisdem/optimization_drivers/nsga2_driver.py
@@ -439,7 +439,7 @@ def run(self):
         desvar_new = design_vars_fronts[0][median_idx, :]
         for name in desvars:
             i, j = self._desvar_idx[name]
-            self.set_design_var(name, desvar_new[i:j])
+            self._set_design_var(name, desvar_new[i:j])
         with RecordingDebugging(self._get_name(), self.iter_count, self) as rec:
             self._run_solve_nonlinear()
             rec.abs = 0.0
@@ -471,7 +471,7 @@ def objective_callback(self, x):
         out_of_bounds = False
         for name in self._designvars:
             i, j = self._desvar_idx[name]
-            self.set_design_var(name, x[i:j])
+            self._set_design_var(name, x[i:j])
 
             # Check that design variables are within bounds
             if (