diff --git a/ci/run_scheduled_sanitizer_test.py b/ci/run_scheduled_sanitizer_test.py
index bc794bf2d8b386b37d972b4b11ac003b482838d4..2aaa49dee678eec94ab7f9b43c1992116a1db59f 100755
--- a/ci/run_scheduled_sanitizer_test.py
+++ b/ci/run_scheduled_sanitizer_test.py
@@ -115,7 +115,7 @@ def run_check(modes: list, out_formats: list, tests: list, run_fec: bool = True)
         )
     )
 
-    with open(CONSOLE_OUT_FILE, "a") as f:
+    with open(CONSOLE_OUT_FILE, "w") as f:
         proc = subprocess.Popen(
             cmd_no_fec, stdout=subprocess.PIPE, stderr=subprocess.PIPE
         )
@@ -174,10 +174,14 @@ def run_check(modes: list, out_formats: list, tests: list, run_fec: bool = True)
         )
     )
 
-    proc = subprocess.Popen(cmd_fec, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-    for c in iter(lambda: proc.stdout.read(1), b""):
-        sys.stdout.buffer.write(c)
-    proc.wait()
+    with open(CONSOLE_OUT_FILE, "a") as f:
+        proc = subprocess.Popen(
+            cmd_fec, stdout=subprocess.PIPE, stderr=subprocess.PIPE
+        )
+        for c in iter(lambda: proc.stdout.read(1), b""):
+            sys.stdout.buffer.write(c)
+            f.write(c.decode("utf8"))
+        proc.wait()
 
     returncode_fec = proc.returncode
     print("returncode_fec:", returncode_fec)