fix for recording with LTM when dealing with broken "sent"-timestamps, like in...

fix for recording with LTM when dealing with broken "sent"-timestamps, like in Proprioception of RobotState Memory.
In this case the frequency filter takes the "arrived" timestamp, as this is normally not broken.

source/RobotAPI/libraries/armem/server/ltm/processors/filter/frequencyFilter/FrequencyFilter.cpp

@@ -23,7 +23,13 @@ namespace armarx::armem::server::ltm::processor::filter
           ARMARX_INFO << "First time this entity is saved";
           auto firstIndex = e.getInstanceIndices()[0];
           auto firstInsance = e.getInstance(firstIndex);
+          
           auto lastT = firstInsance.metadata().sentTime.toMilliSecondsSinceEpoch();
+          if (lastT < 946688400000) {
+            // we assume the timestamp does not make sense if it is older than the year 2000
+            lastT = firstInsance.metadata().arrivedTime.toMilliSecondsSinceEpoch(); //then we take the time it arrived.
+            ARMARX_DEBUG << "sentTime does not make sense. Fix: taking arrivedTime";
+          }
           //for statistics sake:
           auto end = std::chrono::high_resolution_clock::now();
           stats.end_time = end;
@@ -39,11 +45,24 @@ namespace armarx::armem::server::ltm::processor::filter
             // check if any one of the instances for this snapshot were sent in the last x
             // milliseconds since a snapshot was accepted last for this entity:
             e.forEachInstance([this, &instances_accepted, &current, &lastTime](armem::wm::EntityInstance& i){
-                int difference = std::abs(i.metadata().sentTime.toMilliSecondsSinceEpoch() - lastTime);
-                if(difference > this->maxDifference){ //at least one instance is older than the last saved instance
-                    instances_accepted = true;
-                    current = i.metadata().sentTime.toMilliSecondsSinceEpoch();
+                bool sentTimeOkay = true;
+                if (i.metadata().sentTime.toMilliSecondsSinceEpoch() < 946688400000){
+                    sentTimeOkay = false;
                 }
+                if(sentTimeOkay){
+                    int difference = std::abs(i.metadata().sentTime.toMilliSecondsSinceEpoch() - lastTime);
+                    if(difference > this->maxDifference){ //at least one instance is older than the last saved instance
+                        instances_accepted = true;
+                        current = i.metadata().sentTime.toMilliSecondsSinceEpoch();
+                    }
+                } else {
+                    int difference = std::abs(i.metadata().arrivedTime.toMilliSecondsSinceEpoch() - lastTime);
+                    if(difference > this->maxDifference){ //at least one instance is older than the last saved instance
+                        instances_accepted = true;
+                        current = i.metadata().arrivedTime.toMilliSecondsSinceEpoch();
+                    }
+                }
+                
             });
 
             if(instances_accepted){ //if one of the instances was accepted the time when an