From da7693b078f26e753d8e657427e9e7e85b4baa20 Mon Sep 17 00:00:00 2001
From: Giulio Eulisse <10544+ktf@users.noreply.github.com>
Date: Fri, 8 May 2026 16:08:21 +0200
Subject: [PATCH] Another attempt

---
 Framework/Core/src/CommonServices.cxx | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Framework/Core/src/CommonServices.cxx b/Framework/Core/src/CommonServices.cxx
index 0f53f5a6be5a1..13843a2df59a0 100644
--- a/Framework/Core/src/CommonServices.cxx
+++ b/Framework/Core/src/CommonServices.cxx
@@ -701,9 +701,16 @@ o2::framework::ServiceSpec
       O2_SIGNPOST_ID_FROM_POINTER(cid, data_processor_context, &decongestion);
       O2_SIGNPOST_EVENT_EMIT(data_processor_context, cid, "oldest_possible_timeslice", "Received oldest possible timeframe %" PRIu64 " from channel %d",
                              (uint64_t)oldestPossibleTimeslice, channel.value);
+      auto previousOldestPossibleInput = timesliceIndex.getOldestPossibleInput();
       relayer.setOldestPossibleInput({oldestPossibleTimeslice}, channel);
       timesliceIndex.updateOldestPossibleOutput(decongestion.nextEnumerationTimesliceRewinded);
       auto oldestPossibleOutput = relayer.getOldestPossibleOutput();
+      // If the oldest possible input changed, we need to rescan all slots
+      // so that completion policies which depend on it (e.g.
+      // consumeWhenPastOldestPossibleTimeframe) get re-evaluated.
+      if (previousOldestPossibleInput.timeslice.value != timesliceIndex.getOldestPossibleInput().timeslice.value) {
+        timesliceIndex.rescan();
+      }
 
       if (oldestPossibleOutput.timeslice.value == decongestion.lastTimeslice) {
         O2_SIGNPOST_EVENT_EMIT(data_processor_context, cid, "oldest_possible_timeslice", "Synchronous: Not sending already sent value: %" PRIu64, (uint64_t)oldestPossibleOutput.timeslice.value);