diff --git a/Sources/NIOHTTP1/HTTPDecoder.swift b/Sources/NIOHTTP1/HTTPDecoder.swift
index a0d2447e60..2e3a61e7b3 100644
--- a/Sources/NIOHTTP1/HTTPDecoder.swift
+++ b/Sources/NIOHTTP1/HTTPDecoder.swift
@@ -465,8 +465,7 @@ public final class HTTPDecoder<In, Out>: ByteToMessageDecoder, HTTPDecoderDelega
     ///
     /// - parameters:
     ///     - leftOverBytesStrategy: The strategy to use when removing the decoder from the pipeline and an upgrade was,
-    ///                              detected. Note that this does not affect what happens on EOF (in which case an
-    ///                              `ByteToMessageDecoderError.leftoverDataWhenDone` error is fired.)
+    ///                              detected. Note that this does not affect what happens on EOF.
     public init(leftOverBytesStrategy: RemoveAfterUpgradeStrategy = .dropBytes) {
         self.headers.reserveCapacity(16)
         if In.self == HTTPServerRequestPart.self {
@@ -620,18 +619,16 @@ public final class HTTPDecoder<In, Out>: ByteToMessageDecoder, HTTPDecoderDelega
                 try self.feedEOF(context: context)
             }
         }
-        if buffer.readableBytes > 0 {
-            if seenEOF {
+        if buffer.readableBytes > 0 && !seenEOF {
+            // We only do this if we haven't seen EOF because the left-overs strategy must only be invoked when we're
+            // sure that this is the completion of an upgrade.
+            switch self.leftOverBytesStrategy {
+            case .dropBytes:
+                ()
+            case .fireError:
                 context.fireErrorCaught(ByteToMessageDecoderError.leftoverDataWhenDone(buffer))
-            } else {
-                switch self.leftOverBytesStrategy {
-                case .dropBytes:
-                    ()
-                case .fireError:
-                    context.fireErrorCaught(ByteToMessageDecoderError.leftoverDataWhenDone(buffer))
-                case .forwardBytes:
-                    context.fireChannelRead(NIOAny(buffer))
-                }
+            case .forwardBytes:
+                context.fireChannelRead(NIOAny(buffer))
             }
         }
         return .needMoreData
diff --git a/Tests/NIOHTTP1Tests/HTTPDecoderTest+XCTest.swift b/Tests/NIOHTTP1Tests/HTTPDecoderTest+XCTest.swift
index dbd25c0a71..f026e4258c 100644
--- a/Tests/NIOHTTP1Tests/HTTPDecoderTest+XCTest.swift
+++ b/Tests/NIOHTTP1Tests/HTTPDecoderTest+XCTest.swift
@@ -46,7 +46,7 @@ extension HTTPDecoderTest {
                 ("testDoesNotDeliverLeftoversUnnecessarily", testDoesNotDeliverLeftoversUnnecessarily),
                 ("testHTTPResponseWithoutHeaders", testHTTPResponseWithoutHeaders),
                 ("testBasicVerifications", testBasicVerifications),
-                ("testErrorFiredOnEOFForLeftOversInAllLeftOversModes", testErrorFiredOnEOFForLeftOversInAllLeftOversModes),
+                ("testNothingHappensOnEOFForLeftOversInAllLeftOversModes", testNothingHappensOnEOFForLeftOversInAllLeftOversModes),
                 ("testBytesCanBeForwardedWhenHandlerRemoved", testBytesCanBeForwardedWhenHandlerRemoved),
                 ("testBytesCanBeFiredAsErrorWhenHandlerRemoved", testBytesCanBeFiredAsErrorWhenHandlerRemoved),
                 ("testBytesCanBeDroppedWhenHandlerRemoved", testBytesCanBeDroppedWhenHandlerRemoved),
diff --git a/Tests/NIOHTTP1Tests/HTTPDecoderTest.swift b/Tests/NIOHTTP1Tests/HTTPDecoderTest.swift
index 7fb4b7a90c..4b7b6bb7b9 100644
--- a/Tests/NIOHTTP1Tests/HTTPDecoderTest.swift
+++ b/Tests/NIOHTTP1Tests/HTTPDecoderTest.swift
@@ -594,24 +594,14 @@ class HTTPDecoderTest: XCTestCase {
                                                                         decoderFactory: { HTTPRequestDecoder() }))
     }
 
-    func testErrorFiredOnEOFForLeftOversInAllLeftOversModes() throws {
+    func testNothingHappensOnEOFForLeftOversInAllLeftOversModes() throws {
         class Receiver: ChannelInboundHandler {
             typealias InboundIn = HTTPServerRequestPart
 
-            private let errorReceivedPromise: EventLoopPromise<ByteToMessageDecoderError>
             private var numberOfErrors = 0
 
-            init(errorReceivedPromise: EventLoopPromise<ByteToMessageDecoderError>) {
-                self.errorReceivedPromise = errorReceivedPromise
-            }
-
             func errorCaught(context: ChannelHandlerContext, error: Error) {
-                self.numberOfErrors += 1
-                if self.numberOfErrors == 1, let error = error as? ByteToMessageDecoderError {
-                    self.errorReceivedPromise.succeed(error)
-                } else {
-                    XCTFail("illegal: number of errors: \(self.numberOfErrors), error: \(error)")
-                }
+                XCTFail("unexpected error: \(error)")
             }
 
             func channelRead(context: ChannelHandlerContext, data: NIOAny) {
@@ -629,24 +619,14 @@ class HTTPDecoderTest: XCTestCase {
 
         for leftOverBytesStrategy in [RemoveAfterUpgradeStrategy.dropBytes, .fireError, .forwardBytes] {
             let channel = EmbeddedChannel()
-            let errorReceivedPromise: EventLoopPromise<ByteToMessageDecoderError> = channel.eventLoop.makePromise()
             var buffer = channel.allocator.buffer(capacity: 64)
             buffer.writeStaticString("OPTIONS * HTTP/1.1\r\nHost: L\r\nUpgrade: P\r\nConnection: upgrade\r\n\r\nXXXX")
 
             let decoder = HTTPRequestDecoder(leftOverBytesStrategy: leftOverBytesStrategy)
             XCTAssertNoThrow(try channel.pipeline.addHandler(ByteToMessageHandler(decoder)).wait())
-            XCTAssertNoThrow(try channel.pipeline.addHandler(Receiver(errorReceivedPromise: errorReceivedPromise)).wait())
+            XCTAssertNoThrow(try channel.pipeline.addHandler(Receiver()).wait())
             XCTAssertNoThrow(try channel.writeInbound(buffer))
             XCTAssertNoThrow(XCTAssert(try channel.finish().isClean))
-
-            switch Result(catching: { try errorReceivedPromise.futureResult.wait() }) {
-            case .success(ByteToMessageDecoderError.leftoverDataWhenDone(let buffer)):
-                XCTAssertEqual("XXXX", String(decoding: buffer.readableBytesView, as: Unicode.UTF8.self))
-            case .failure(let error):
-                XCTFail("unexpected error: \(error)")
-            case .success(let error):
-                XCTFail("unexpected error: \(error)")
-            }
         }
     }