diff --git a/esphome/core/scheduler.cpp b/esphome/core/scheduler.cpp
index 5d0b96c38f2..1dc95c448b6 100644
--- a/esphome/core/scheduler.cpp
+++ b/esphome/core/scheduler.cpp
@@ -442,10 +442,10 @@ uint32_t HOT Scheduler::call(uint32_t now) {
 
       SchedulerNameLog name_log;
       bool is_cancelled = is_item_removed_(item);
-      ESP_LOGD(TAG, "  %s '%s/%s' interval=%" PRIu32 " next_execution in %" PRIu64 "ms at %" PRIu64 "%s",
+      ESP_LOGD(TAG, "  %s '%s/%s' interval=%" PRIu32 " next_execution in %" PRId64 "ms at %" PRIu64 "%s",
                LOG_STR_ARG(item->get_type_str()), LOG_STR_ARG(item->get_source()),
                name_log.format(item->get_name_type(), item->get_name(), item->get_name_hash_or_id()), item->interval,
-               item->get_next_execution() - now_64, item->get_next_execution(),
+               (int64_t) (item->get_next_execution() - now_64), item->get_next_execution(),
                is_cancelled ? LOG_STR_LITERAL(" [CANCELLED]") : LOG_STR_LITERAL(""));
 
       old_items.push_back(item);
@@ -539,6 +539,7 @@ uint32_t HOT Scheduler::call(uint32_t now) {
       // We were removed/cancelled in the function call, recycle and continue
       this->to_remove_decrement_locked_();
       this->recycle_item_main_loop_(executed_item);
+      has_added_items |= !this->to_add_.empty();
       continue;
     }
 
diff --git a/tests/components/core/test_scheduler_cancelled_callback.cpp b/tests/components/core/test_scheduler_cancelled_callback.cpp
new file mode 100644
index 00000000000..b4cfd21cc5c
--- /dev/null
+++ b/tests/components/core/test_scheduler_cancelled_callback.cpp
@@ -0,0 +1,44 @@
+#include "esphome/core/component.h"
+#include "esphome/core/hal.h"
+#include "esphome/core/scheduler.h"
+
+#include <gtest/gtest.h>
+
+#include <chrono>
+#include <thread>
+
+namespace esphome::core::testing {
+
+class SchedulerTestComponent : public Component {};
+
+// On a multi-threaded build next_schedule_in() only sees items_, so a timeout a callback leaves in
+// to_add_ would let a loop that sleeps on next_schedule_in() oversleep. The case that used to skip
+// the merge is a heap item (a zero timeout would run from the defer queue instead) whose callback
+// cancels its own item.
+TEST(Scheduler, TimeoutAddedByACancelledCallbackIsVisibleAfterCall) {
+  Scheduler scheduler;
+  SchedulerTestComponent component;
+  bool fired = false;
+
+  scheduler.set_timeout(&component, "first", 1, [&]() {
+    scheduler.cancel_timeout(&component, "first");
+    scheduler.set_timeout(&component, "second", 100, [&fired]() { fired = true; });
+  });
+  std::this_thread::sleep_for(std::chrono::milliseconds(5));
+  scheduler.call(millis());
+
+  auto next = scheduler.next_schedule_in(millis());
+  ASSERT_TRUE(next.has_value());
+  const uint32_t next_ms = next.has_value() ? *next : 0;
+  EXPECT_GT(next_ms, 50u);
+  EXPECT_LE(next_ms, 100u);
+  EXPECT_FALSE(fired);
+
+  std::this_thread::sleep_for(std::chrono::milliseconds(120));
+  scheduler.call(millis());
+  EXPECT_TRUE(fired);
+  EXPECT_FALSE(scheduler.next_schedule_in(millis()).has_value());
+  scheduler.trim_freelist();
+}
+
+}  // namespace esphome::core::testing