added check for timestamp

application/src/main/java/org/thingsboard/server/controller/CalculatedFieldController.java

@@ -279,7 +279,7 @@ public class CalculatedFieldController extends BaseController {
                 lastUpdateTimestamp = Math.max(lastUpdateTimestamp, maxTs);
             }
         }
-        return lastUpdateTimestamp;
+        return lastUpdateTimestamp == -1 ? System.currentTimeMillis() : lastUpdateTimestamp;
     }
 
     private <E extends HasId<I> & HasTenantId, I extends EntityId> void checkReferencedEntities(CalculatedFieldConfiguration calculatedFieldConfig, SecurityUser user) throws ThingsboardException {

application/src/main/java/org/thingsboard/server/service/cf/ctx/state/BaseCalculatedFieldState.java

@@ -113,10 +113,8 @@ public abstract class BaseCalculatedFieldState implements CalculatedFieldState {
         if (entry instanceof SingleValueArgumentEntry singleValueArgumentEntry) {
             this.lastUpdateTimestamp = singleValueArgumentEntry.getTs();
         } else if (entry instanceof TsRollingArgumentEntry tsRollingArgumentEntry) {
-            Map.Entry<Long, Double> lastEntry = tsRollingArgumentEntry.getTsRecords().pollLastEntry();
-            if (lastEntry != null) {
-                this.lastUpdateTimestamp = lastEntry.getKey();
-            }
+            Map.Entry<Long, Double> lastEntry = tsRollingArgumentEntry.getTsRecords().lastEntry();
+            this.lastUpdateTimestamp = (lastEntry != null) ? lastEntry.getKey() : System.currentTimeMillis();
         }
     }