diff --git a/Framework/Core/src/CompletionPolicyHelpers.cxx b/Framework/Core/src/CompletionPolicyHelpers.cxx
index 5c38446fedaee..769692c1d6637 100644
--- a/Framework/Core/src/CompletionPolicyHelpers.cxx
+++ b/Framework/Core/src/CompletionPolicyHelpers.cxx
@@ -15,6 +15,7 @@
 #include "Framework/DeviceSpec.h"
 #include "Framework/CompilerBuiltins.h"
 #include "Framework/Logger.h"
+#include "Framework/TimesliceIndex.h"
 #include "Framework/TimingInfo.h"
 #include "DecongestionService.h"
 
@@ -107,10 +108,32 @@ CompletionPolicy CompletionPolicyHelpers::consumeWhenAll(const char* name, Compl
 {
   auto callback = [](InputSpan const& inputs, std::vector<InputSpec> const& specs, ServiceRegistryRef& ref) -> CompletionPolicy::CompletionOp {
     assert(inputs.size() == spec.size());
+
+    size_t si = 0;
+    bool missingSporadic = false;
+    size_t currentTimeslice = -1;
     for (auto& input : inputs) {
-      if (input.header == nullptr) {
+      assert(si < specs.size());
+      auto& spec = specs[si++];
+      if (input.header == nullptr && spec.lifetime != Lifetime::Sporadic) {
         return CompletionPolicy::CompletionOp::Wait;
       }
+      if (input.header == nullptr && spec.lifetime == Lifetime::Sporadic) {
+        missingSporadic |= true;
+      }
+      if (input.header != nullptr) {
+        auto const* dph = framework::DataRefUtils::getHeader<o2::framework::DataProcessingHeader*>(input);
+        if (dph && !TimingInfo::timesliceIsTimer(dph->startTime)) {
+          currentTimeslice = dph->startTime;
+          break;
+        }
+      }
+    }
+    // If some sporadic inputs are missing, we wait for them util we are sure they will not come,
+    // i.e. until the oldest possible timeslice is beyond the timeslice of the input.
+    auto& timesliceIndex = ref.get<TimesliceIndex>();
+    if (missingSporadic && currentTimeslice >= timesliceIndex.getOldestPossibleInput().timeslice.value) {
+      return CompletionPolicy::CompletionOp::Wait;
     }
     return CompletionPolicy::CompletionOp::Consume;
   };