diff --git a/modules/rtp_rtcp/source/rtp_packet_history.cc b/modules/rtp_rtcp/source/rtp_packet_history.cc
index e1374feb57..211077bf36 100644
--- a/modules/rtp_rtcp/source/rtp_packet_history.cc
+++ b/modules/rtp_rtcp/source/rtp_packet_history.cc
@@ -97,6 +97,15 @@ void RtpPacketHistory::PutRtpPacket(std::unique_ptr<RtpPacketToSend> packet,
   const uint16_t rtp_seq_no = packet->SequenceNumber();
   StoredPacket& stored_packet = packet_history_[rtp_seq_no];
   RTC_DCHECK(stored_packet.packet == nullptr);
+  if (stored_packet.packet) {
+    // It is an error if this happen. But it can happen if the sequence numbers
+    // for some reason restart without that the history has been reset.
+    auto size_iterator = packet_size_.find(stored_packet.packet->size());
+    if (size_iterator != packet_size_.end() &&
+        size_iterator->second == stored_packet.packet->SequenceNumber()) {
+      packet_size_.erase(size_iterator);
+    }
+  }
   stored_packet.packet = std::move(packet);
 
   if (stored_packet.packet->capture_time_ms() <= 0) {
@@ -209,8 +218,19 @@ std::unique_ptr<RtpPacketToSend> RtpPacketHistory::GetBestFittingPacket(
   const uint16_t seq_no = upper_bound_diff < lower_bound_diff
                               ? size_iter_upper->second
                               : size_iter_lower->second;
-  RtpPacketToSend* best_packet =
-      packet_history_.find(seq_no)->second.packet.get();
+  auto history_it = packet_history_.find(seq_no);
+  if (history_it == packet_history_.end()) {
+    RTC_LOG(LS_ERROR) << "Can't find packet in history with seq_no" << seq_no;
+    RTC_DCHECK(false);
+    return nullptr;
+  }
+  if (!history_it->second.packet) {
+    RTC_LOG(LS_ERROR) << "Packet pointer is null in history for seq_no"
+                      << seq_no;
+    RTC_DCHECK(false);
+    return nullptr;
+  }
+  RtpPacketToSend* best_packet = history_it->second.packet.get();
   return absl::make_unique<RtpPacketToSend>(*best_packet);
 }