diff --git a/src/net_processing.cpp b/src/net_processing.cpp
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -45,6 +45,8 @@
 static constexpr int64_t ORPHAN_TX_EXPIRE_TIME = 20 * 60;
 /** Minimum time between orphan transactions expire time checks in seconds */
 static constexpr int64_t ORPHAN_TX_EXPIRE_INTERVAL = 5 * 60;
+/** How long to cache transactions in mapRelay for normal relay */
+static constexpr std::chrono::seconds RELAY_TX_CACHE_TIME{15 * 60};
 /**
  * Headers download timeout expressed in microseconds.
  * Timeout = base + per_header * (expected number of headers)
@@ -1711,6 +1713,13 @@
     // messages from this peer (likely resulting in our peer eventually
     // disconnecting us).
     if (pfrom->m_tx_relay != nullptr) {
+        // mempool entries added before this time have likely expired from
+        // mapRelay
+        const std::chrono::seconds longlived_mempool_time =
+            GetTime<std::chrono::seconds>() - RELAY_TX_CACHE_TIME;
+        const std::chrono::seconds mempool_req =
+            pfrom->m_tx_relay->m_last_mempool_req.load();
+
         LOCK(cs_main);
 
         while (it != pfrom->vRecvGetData.end() && it->type == MSG_TX) {
@@ -1734,14 +1743,15 @@
                     pfrom,
                     msgMaker.Make(nSendFlags, NetMsgType::TX, *mi->second));
                 push = true;
-            } else if (pfrom->m_tx_relay->m_last_mempool_req.load().count()) {
+            } else {
                 auto txinfo = g_mempool.info(TxId(inv.hash));
                 // To protect privacy, do not answer getdata using the mempool
                 // when that TX couldn't have been INVed in reply to a MEMPOOL
-                // request.
+                // request, or when it's too recent to have expired from
+                // mapRelay.
                 if (txinfo.tx &&
-                    txinfo.m_time <=
-                        pfrom->m_tx_relay->m_last_mempool_req.load()) {
+                    ((mempool_req.count() && txinfo.m_time <= mempool_req) ||
+                     (txinfo.m_time <= longlived_mempool_time))) {
                     connman->PushMessage(
                         pfrom,
                         msgMaker.Make(nSendFlags, NetMsgType::TX, *txinfo.tx));
@@ -4755,8 +4765,12 @@
                         auto ret = mapRelay.insert(
                             std::make_pair(txid, std::move(txinfo.tx)));
                         if (ret.second) {
-                            vRelayExpiration.push_back(std::make_pair(
-                                nNow + 15 * 60 * 1000000, ret.first));
+                            vRelayExpiration.push_back(
+                                std::make_pair(nNow +
+                                                   std::chrono::microseconds{
+                                                       RELAY_TX_CACHE_TIME}
+                                                       .count(),
+                                               ret.first));
                         }
                     }
                     if (vInv.size() == MAX_INV_SZ) {