diff --git a/httpcore5/src/main/java/org/apache/hc/core5/pool/RouteSegmentedConnPool.java b/httpcore5/src/main/java/org/apache/hc/core5/pool/RouteSegmentedConnPool.java
index fb331e221..88f516053 100644
--- a/httpcore5/src/main/java/org/apache/hc/core5/pool/RouteSegmentedConnPool.java
+++ b/httpcore5/src/main/java/org/apache/hc/core5/pool/RouteSegmentedConnPool.java
@@ -172,10 +172,11 @@ public RouteSegmentedConnPool(
         this.timeouts = new ScheduledThreadPoolExecutor(1, tf);
         this.timeouts.setRemoveOnCancelPolicy(true);
 
-        // Asynchronous disposer for slow GRACEFUL closes.
+        // Asynchronous disposer for slow GRACEFUL closes. Capped at 32 so very
+        // many-core boxes do not over-provision; threads time out when idle.
         final int cores = Math.max(2, Runtime.getRuntime().availableProcessors());
-        final int nThreads = Math.min(8, cores);
-        final int qsize = 1024;
+        final int nThreads = Math.min(32, Math.max(8, cores * 2));
+        final int qsize = 4096;
 
         final ThreadFactory df = r -> {
             final Thread t = new Thread(r, "seg-pool-disposer");
@@ -184,10 +185,11 @@ public RouteSegmentedConnPool(
         };
         this.disposer = new ThreadPoolExecutor(
                 nThreads, nThreads,
-                0L, TimeUnit.MILLISECONDS,
+                30_000L, TimeUnit.MILLISECONDS,
                 new LinkedBlockingQueue<>(qsize),
                 df,
                 new ThreadPoolExecutor.AbortPolicy());
+        this.disposer.allowCoreThreadTimeOut(true);
     }
 
     final class Segment {
@@ -293,19 +295,21 @@ public Future<PoolEntry<R, C>> lease(
         // Late hit after enqueuing
         final PoolEntry<R, C> late = pollAvailable(seg, state);
         if (late != null) {
-            if (seg.waiters.remove(w)) {
+            if (w.complete(late)) {
                 cancelTimeout(w);
                 fireOnLease(route);
                 if (callback != null) {
                     callback.completed(late);
                 }
-                w.complete(late);
                 dequeueIfDrained(seg);
                 return w;
             } else {
                 boolean handedOff = false;
                 for (Waiter other; (other = seg.waiters.pollFirst()) != null; ) {
-                    if (!other.cancelled && compatible(other.state, late.getState())) {
+                    if (other.cancelled || other.isDone()) {
+                        continue;
+                    }
+                    if (compatible(other.state, late.getState())) {
                         cancelTimeout(other);
                         handedOff = other.complete(late);
                         if (handedOff) {
@@ -361,8 +365,10 @@ public void release(final PoolEntry<R, C> entry, final boolean reusable) {
         if (stillValid) {
             if (!handOffToCompatibleWaiter(entry, seg)) {
                 offerAvailable(seg, entry);
-                enqueueIfNeeded(route, seg);
-                triggerDrainIfMany();
+                if (!seg.waiters.isEmpty()) {
+                    enqueueIfNeeded(route, seg);
+                    triggerDrainIfMany();
+                }
             }
         } else {
             discardAndDecr(entry, CloseMode.GRACEFUL);
@@ -612,7 +618,7 @@ private boolean compatible(final Object needed, final Object have) {
     }
 
     private boolean handOffToCompatibleWaiter(final PoolEntry<R, C> entry, final Segment seg) {
-        final Deque<Waiter> skipped = new ArrayDeque<>();
+        Deque<Waiter> skipped = null;
         boolean handedOff = false;
 
         for (; ; ) {
@@ -632,12 +638,17 @@ private boolean handOffToCompatibleWaiter(final PoolEntry<R, C> entry, final Seg
                     break;
                 }
             } else {
+                if (skipped == null) {
+                    skipped = new ArrayDeque<>();
+                }
                 skipped.addLast(w);
             }
         }
 
-        while (!skipped.isEmpty()) {
-            seg.waiters.addFirst(skipped.pollLast());
+        if (skipped != null) {
+            while (!skipped.isEmpty()) {
+                seg.waiters.addFirst(skipped.pollLast());
+            }
         }
         return handedOff;
     }