diff --git a/modules/video_coding/codecs/vp9/test/vp9_impl_unittest.cc b/modules/video_coding/codecs/vp9/test/vp9_impl_unittest.cc
index 3ae1c068f9..1f3343d37a 100644
--- a/modules/video_coding/codecs/vp9/test/vp9_impl_unittest.cc
+++ b/modules/video_coding/codecs/vp9/test/vp9_impl_unittest.cc
@@ -1439,4 +1439,78 @@ TEST_F(TestVp9Impl, EncodeWithDynamicRate) {
   ASSERT_TRUE(WaitForEncodedFrame(&encoded_frame, &codec_specific_info));
 }
 
+TEST_F(TestVp9Impl, ReenablingUpperLayerAfterKFWithInterlayerPredIsEnabled) {
+  const size_t num_spatial_layers = 2;
+  const int num_frames_to_encode = 10;
+  codec_settings_.VP9()->flexibleMode = true;
+  codec_settings_.VP9()->frameDroppingOn = false;
+  codec_settings_.VP9()->numberOfSpatialLayers = num_spatial_layers;
+  codec_settings_.VP9()->numberOfTemporalLayers = 1;
+  codec_settings_.VP9()->interLayerPred = InterLayerPredMode::kOn;
+  // Force low frame-rate, so all layers are present for all frames.
+  codec_settings_.maxFramerate = 5;
+
+  ConfigureSvc(num_spatial_layers);
+
+  EXPECT_EQ(WEBRTC_VIDEO_CODEC_OK,
+            encoder_->InitEncode(&codec_settings_, kSettings));
+
+  VideoBitrateAllocation bitrate_allocation;
+  for (size_t sl_idx = 0; sl_idx < num_spatial_layers; ++sl_idx) {
+    bitrate_allocation.SetBitrate(
+        sl_idx, 0, codec_settings_.spatialLayers[sl_idx].targetBitrate * 1000);
+  }
+  encoder_->SetRates(VideoEncoder::RateControlParameters(
+      bitrate_allocation, codec_settings_.maxFramerate));
+
+  std::vector<EncodedImage> encoded_frames;
+  std::vector<CodecSpecificInfo> codec_specific;
+
+  for (int i = 0; i < num_frames_to_encode; ++i) {
+    SetWaitForEncodedFramesThreshold(num_spatial_layers);
+    EXPECT_EQ(WEBRTC_VIDEO_CODEC_OK,
+              encoder_->Encode(*NextInputFrame(), nullptr));
+    ASSERT_TRUE(WaitForEncodedFrames(&encoded_frames, &codec_specific));
+    EXPECT_EQ(encoded_frames.size(), num_spatial_layers);
+  }
+
+  // Disable the last layer.
+  bitrate_allocation.SetBitrate(num_spatial_layers - 1, 0, 0);
+  encoder_->SetRates(VideoEncoder::RateControlParameters(
+      bitrate_allocation, codec_settings_.maxFramerate));
+
+  for (int i = 0; i < num_frames_to_encode; ++i) {
+    SetWaitForEncodedFramesThreshold(num_spatial_layers - 1);
+    EXPECT_EQ(WEBRTC_VIDEO_CODEC_OK,
+              encoder_->Encode(*NextInputFrame(), nullptr));
+    ASSERT_TRUE(WaitForEncodedFrames(&encoded_frames, &codec_specific));
+    EXPECT_EQ(encoded_frames.size(), num_spatial_layers - 1);
+  }
+
+  std::vector<VideoFrameType> frame_types = {VideoFrameType::kVideoFrameKey};
+
+  // Force a key-frame with the last layer still disabled.
+  SetWaitForEncodedFramesThreshold(num_spatial_layers - 1);
+  EXPECT_EQ(WEBRTC_VIDEO_CODEC_OK,
+            encoder_->Encode(*NextInputFrame(), &frame_types));
+  ASSERT_TRUE(WaitForEncodedFrames(&encoded_frames, &codec_specific));
+  EXPECT_EQ(encoded_frames.size(), num_spatial_layers - 1);
+  ASSERT_EQ(encoded_frames[0]._frameType, VideoFrameType::kVideoFrameKey);
+
+  // Re-enable the last layer.
+  bitrate_allocation.SetBitrate(
+      num_spatial_layers - 1, 0,
+      codec_settings_.spatialLayers[num_spatial_layers - 1].targetBitrate *
+          1000);
+  encoder_->SetRates(VideoEncoder::RateControlParameters(
+      bitrate_allocation, codec_settings_.maxFramerate));
+
+  SetWaitForEncodedFramesThreshold(num_spatial_layers);
+  EXPECT_EQ(WEBRTC_VIDEO_CODEC_OK,
+            encoder_->Encode(*NextInputFrame(), nullptr));
+  ASSERT_TRUE(WaitForEncodedFrames(&encoded_frames, &codec_specific));
+  EXPECT_EQ(encoded_frames.size(), num_spatial_layers);
+  EXPECT_EQ(encoded_frames[0]._frameType, VideoFrameType::kVideoFrameDelta);
+}
+
 }  // namespace webrtc
diff --git a/modules/video_coding/codecs/vp9/vp9_impl.cc b/modules/video_coding/codecs/vp9/vp9_impl.cc
index a0f410f186..b57c98b032 100644
--- a/modules/video_coding/codecs/vp9/vp9_impl.cc
+++ b/modules/video_coding/codecs/vp9/vp9_impl.cc
@@ -47,7 +47,7 @@ uint8_t kUpdBufIdx[4] = {0, 0, 1, 0};
 int kMaxNumTiles4kVideo = 8;
 
 // Maximum allowed PID difference for differnet per-layer frame-rate case.
-const int kMaxAllowedPidDIff = 30;
+const int kMaxAllowedPidDiff = 30;
 
 constexpr double kLowRateFactor = 1.0;
 constexpr double kHighRateFactor = 2.0;
@@ -1331,16 +1331,13 @@ vpx_svc_ref_frame_config_t VP9EncoderImpl::SetReferences(
       // not supposed to be used for temporal prediction.
       RTC_DCHECK_LT(buf_idx, kNumVp9Buffers - 1);
 
-      // Sanity check that reference picture number is smaller than current
-      // picture number.
-      RTC_DCHECK_LT(ref_buf_[buf_idx].pic_num, curr_pic_num);
-      const size_t pid_diff = curr_pic_num - ref_buf_[buf_idx].pic_num;
+      const int pid_diff = curr_pic_num - ref_buf_[buf_idx].pic_num;
       // Incorrect spatial layer may be in the buffer due to a key-frame.
       const bool same_spatial_layer =
           ref_buf_[buf_idx].spatial_layer_id == sl_idx;
       bool correct_pid = false;
       if (is_flexible_mode_) {
-        correct_pid = pid_diff < kMaxAllowedPidDIff;
+        correct_pid = pid_diff > 0 && pid_diff < kMaxAllowedPidDiff;
       } else {
         // Below code assumes single temporal referecence.
         RTC_DCHECK_EQ(gof_.num_ref_pics[gof_idx], 1);