diff --git a/lib/amazonka-core/src/Amazonka/Data/Time.hs b/lib/amazonka-core/src/Amazonka/Data/Time.hs
index cad91729da4..626dd127f1d 100644
--- a/lib/amazonka-core/src/Amazonka/Data/Time.hs
+++ b/lib/amazonka-core/src/Amazonka/Data/Time.hs
@@ -107,7 +107,20 @@ parseFormattedTime = do
                   ++ show s
               )
 
-  parse (format (Proxy @RFC822))
+      -- A more lenient format string for parsing RFC822, whose
+      -- grammar allows single-digit days.
+      --
+      -- We still use `%d` over `%-d` in the `TimeFormat RFC822`
+      -- instance to always produce two-digit days, since that is what
+      -- most people expect to see.
+      --
+      -- This allows us to parse responses from versions of
+      -- `rclone serve s3` circa 2024:
+      -- https://github.com/rclone/rclone/issues/8277
+      rfc822 :: String
+      rfc822 = "%a, %-d %b %Y %H:%M:%S %Z"
+
+  parse rfc822
     <|> parse (format (Proxy @ISO8601))
     <|> parse (format (Proxy @BasicTime))
     <|> parse (format (Proxy @AWSTime))
@@ -138,7 +151,7 @@ instance ToText AWSTime where
 instance ToText POSIX where
   toText (Time t) = toText (truncate (utcTimeToPOSIXSeconds t) :: Integer)
 
-renderFormattedTime :: forall a. TimeFormat (Time a) => Time a -> String
+renderFormattedTime :: forall a. (TimeFormat (Time a)) => Time a -> String
 renderFormattedTime (Time t) =
   formatTime
     defaultTimeLocale
diff --git a/lib/amazonka-core/test/Test/Amazonka/Data/Time.hs b/lib/amazonka-core/test/Test/Amazonka/Data/Time.hs
index 49fb969d4e4..6d186b4fe74 100644
--- a/lib/amazonka-core/test/Test/Amazonka/Data/Time.hs
+++ b/lib/amazonka-core/test/Test/Amazonka/Data/Time.hs
@@ -29,6 +29,10 @@ tests =
                 "rfc822 - GMT"
                 "Fri, 07 Nov 2014 04:42:13 GMT"
                 (time :: RFC822),
+              testFromText
+                "rfc822 - GMT - single-digit day"
+                "Fri, 7 Nov 2014 04:42:13 GMT"
+                (time :: RFC822),
               testFromText
                 "rfc822 - PST"
                 "Fri, 06 Nov 2014 20:42:13 PST"
diff --git a/lib/amazonka-core/test/Test/Amazonka/Util.hs b/lib/amazonka-core/test/Test/Amazonka/Util.hs
index 12aff836c7e..bca1866a29b 100644
--- a/lib/amazonka-core/test/Test/Amazonka/Util.hs
+++ b/lib/amazonka-core/test/Test/Amazonka/Util.hs
@@ -29,19 +29,19 @@ doc =
 newtype X a = X a
   deriving stock (Eq, Show)
 
-instance ToQuery a => ToQuery (X a) where
+instance (ToQuery a) => ToQuery (X a) where
   toQuery (X x) = "x" =: x
 
-instance FromXML a => FromXML (X a) where
+instance (FromXML a) => FromXML (X a) where
   parseXML = fmap X . parseXML
 
-instance ToXML a => ToElement (X a) where
+instance (ToXML a) => ToElement (X a) where
   toElement (X x) = mkElement "x" x
 
-instance FromJSON a => FromJSON (X a) where
+instance (FromJSON a) => FromJSON (X a) where
   parseJSON = withObject "X" (fmap X . (.: "x"))
 
-instance ToJSON a => ToJSON (X a) where
+instance (ToJSON a) => ToJSON (X a) where
   toJSON (X x) = object ["x" .= x]
 
 testFromText ::
@@ -50,7 +50,7 @@ testFromText ::
   Text ->
   a ->
   TestTree
-testFromText n t x = testCase n (Right x @?= fromText t)
+testFromText n t x = testCase n (Right x @=? fromText t)
 
 testToText ::
   (ToText a, Show a, Eq a) =>
@@ -58,7 +58,7 @@ testToText ::
   Text ->
   a ->
   TestTree
-testToText n t x = testCase n (t @?= toText x)
+testToText n t x = testCase n (t @=? toText x)
 
 testToQuery ::
   (ToQuery a, Show a, Eq a) =>
@@ -76,7 +76,7 @@ testFromXML ::
   TestTree
 testFromXML n bs x =
   testCase n $
-    Right (X x) @?= (decodeXML (wrapXML bs) >>= parseXML)
+    (decodeXML (wrapXML bs) >>= parseXML) @=? Right (X x)
 
 testToXML ::
   (ToXML a, Show a, Eq a) =>
@@ -84,7 +84,7 @@ testToXML ::
   ByteStringLazy ->
   a ->
   TestTree
-testToXML n bs x = testCase n $ wrapXML bs @?= encodeXML (X x)
+testToXML n bs x = testCase n $ wrapXML bs @=? encodeXML (X x)
 
 testFromJSON ::
   (FromJSON a, Show a, Eq a) =>
@@ -94,7 +94,7 @@ testFromJSON ::
   TestTree
 testFromJSON n bs x =
   testCase n $
-    Right (X x) @?= eitherDecode' ("{\"x\":" <> bs <> "}")
+    eitherDecode' ("{\"x\":" <> bs <> "}") @=? Right (X x)
 
 testToJSON ::
   (ToJSON a, Show a, Eq a) =>
@@ -102,7 +102,7 @@ testToJSON ::
   ByteStringLazy ->
   a ->
   TestTree
-testToJSON n bs x = testCase n (bs @?= Aeson.encode x)
+testToJSON n bs x = testCase n (bs @=? Aeson.encode x)
 
 str :: ByteStringLazy -> ByteStringLazy
 str bs = "\"" <> bs <> "\""
@@ -117,5 +117,5 @@ maxInt = maxBound
 minInt :: Int
 minInt = minBound
 
-toLazyBS :: ToByteString a => a -> ByteStringLazy
+toLazyBS :: (ToByteString a) => a -> ByteStringLazy
 toLazyBS = LBS.fromStrict . toBS
diff --git a/lib/amazonka/CHANGELOG.md b/lib/amazonka/CHANGELOG.md
index b4eea49eb2b..942c5f71158 100644
--- a/lib/amazonka/CHANGELOG.md
+++ b/lib/amazonka/CHANGELOG.md
@@ -32,6 +32,8 @@
 
 ### Fixed
 
+- `amazonka-core`: Accept single-digit days when parsing RFC822 dates
+[\#1032](https://github.com/brendanhay/amazonka/pull/1032)
 - `amazonka-core`: Fixed the sorting of query parameters during request canonicalisation. In rare cases, it could sort incorrectly, resulting in requests that failed signature verification.
 [\#1031](https://github.com/brendanhay/amazonka/pull/1031)
 - `amazonka`: Attempt to load credentials in the correct order. In particular, this means that the IMDS is queried last and is once again consistent with other SDKs.