diff --git a/moto/moto_server/werkzeug_app.py b/moto/moto_server/werkzeug_app.py
index 14f855174..234a74d47 100644
--- a/moto/moto_server/werkzeug_app.py
+++ b/moto/moto_server/werkzeug_app.py
@@ -201,7 +201,7 @@ class DomainDispatcherApplication:
         finally:
             if body:
                 # We've consumed the body = need to reset it
-                environ["wsgi.input"] = io.StringIO(body)
+                environ["wsgi.input"] = io.BytesIO(body.encode("utf-8"))
         return body
 
     def get_service_from_body(
diff --git a/tests/test_core/test_account_id_resolution.py b/tests/test_core/test_account_id_resolution.py
index d5d5b56bd..b4df22532 100644
--- a/tests/test_core/test_account_id_resolution.py
+++ b/tests/test_core/test_account_id_resolution.py
@@ -57,6 +57,7 @@ class TestAccountIdResolution:
         headers = {
             "Authorization": "AWS4-HMAC-SHA256 Credential=abcd/20010101/us-east-2/sts/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date, Signature=...",
             "Content-Length": f"{len(data)}",
+            "Content-Type": "application/x-www-form-urlencoded",
         }
         headers.update(extra_headers or {})
         return requests.post(f"{BASE_URL}", headers=headers, data=data)
diff --git a/tests/test_moto_api/recorder/__init__.py b/tests/test_moto_api/recorder/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/tests/test_moto_api/recorder/test_recorder.py b/tests/test_moto_api/recorder/test_recorder.py
index f716b3d63..5eef59190 100644
--- a/tests/test_moto_api/recorder/test_recorder.py
+++ b/tests/test_moto_api/recorder/test_recorder.py
@@ -1,3 +1,4 @@
+import base64
 import boto3
 import json
 import requests
@@ -81,8 +82,13 @@ class TestRecorder(TestCase):
 
         content = json.loads(self._download_recording())
 
-        content.should.have.key("body").should.contain("Action=RunInstances")
-        content.should.have.key("body").should.contain(f"ImageId={EXAMPLE_AMI_ID}")
+        if content.get("body_encoded"):
+            body = base64.b64decode(content.get("body")).decode("ascii")
+        else:
+            body = content["body"]
+
+        body.should.contain("Action=RunInstances")
+        body.should.contain(f"ImageId={EXAMPLE_AMI_ID}")
 
     def test_multiple_services(self):
         self._start_recording()
diff --git a/tests/test_s3/test_server.py b/tests/test_s3/test_server.py
index 3f60fb831..a971b4ec3 100644
--- a/tests/test_s3/test_server.py
+++ b/tests/test_s3/test_server.py
@@ -36,12 +36,8 @@ def test_s3_server_get():
     res.data.should.contain(b"ListAllMyBucketsResult")
 
 
-@pytest.mark.parametrize("key_name", ["bar_baz", "baz bar"])
+@pytest.mark.parametrize("key_name", ["bar_baz", "bar+baz", "baz bar"])
 def test_s3_server_bucket_create(key_name):
-    # Very similar test in test_s3.py::test_get_object_versions_with_prefix
-    # That test also includes a key containing a +, such as 'baz+bar'
-    # We cannot test that example here, because Werkzeug (as of 2.3.0) will helpfully normalize that to `baz bar`
-    # TODO: re-enable this key-name if/when we ever replace Werkzeug
     test_client = authenticated_client()
 
     res = test_client.put("/", "http://foobaz.localhost:5000/")