diff --git a/src/shared/runtime-rpc-call-queue.ts b/src/shared/runtime-rpc-call-queue.ts
index dcf4015078..7a3c184260 100644
--- a/src/shared/runtime-rpc-call-queue.ts
+++ b/src/shared/runtime-rpc-call-queue.ts
@@ -30,9 +30,9 @@ type QueuedRuntimeCall<T> = {
 type RuntimeCallQueue = {
   active: number
   backgroundActive: number
-  foreground: QueuedRuntimeCall<unknown>[]
+  foreground: (QueuedRuntimeCall<unknown> | undefined)[]
   foregroundHead: number
-  background: QueuedRuntimeCall<unknown>[]
+  background: (QueuedRuntimeCall<unknown> | undefined)[]
   backgroundHead: number
 }
 
@@ -202,6 +202,7 @@ export class RuntimeRpcCallQueuePool {
       return undefined
     }
     const call = queue.foreground[queue.foregroundHead]
+    queue.foreground[queue.foregroundHead] = undefined
     queue.foregroundHead += 1
     this.queuedCallCount = Math.max(0, this.queuedCallCount - 1)
     this.compactForeground(queue)
@@ -213,6 +214,7 @@ export class RuntimeRpcCallQueuePool {
       return undefined
     }
     const call = queue.background[queue.backgroundHead]
+    queue.background[queue.backgroundHead] = undefined
     queue.backgroundHead += 1
     this.queuedCallCount = Math.max(0, this.queuedCallCount - 1)
     this.compactBackground(queue)
@@ -223,8 +225,7 @@ export class RuntimeRpcCallQueuePool {
     if (queue.foregroundHead <= 32 || queue.foregroundHead * 2 < queue.foreground.length) {
       return
     }
-    // Why: large remote-runtime refresh bursts can queue many calls;
-    // head indexes avoid O(n) shift costs while compaction releases closures.
+    // Head indexes avoid repeated shifts; compaction bounds the consumed prefix.
     queue.foreground.splice(0, queue.foregroundHead)
     queue.foregroundHead = 0
   }