diff --git a/test/test_maxima.py b/test/test_maxima.py
index ddb5c764085cb20e618c20e34c56fef5789e43eb..441884c2055c54f2e18dfa9d7a0ee4d57acaffbf 100644
--- a/test/test_maxima.py
+++ b/test/test_maxima.py
@@ -145,8 +145,10 @@ def test_diff():
 
 @pytest.mark.skipif(MAXIMA_UNAVAILABLE, reason="maxima cannot be launched")
 def test_long_command(knl):
-    from pymbolic.interop.maxima import set_debug
-    set_debug(4)
+    # Seems to fail with an encoding error on pexpect 4.8 and Py3.8.
+    # -AK, 2020-07-13
+    # from pymbolic.interop.maxima import set_debug
+    # set_debug(4)
     knl.eval_str("+".join(["1"]*16384))