add comment

register-core/src/main/java/org/opengroup/osdu/register/di/GroupVmCache.java

@@ -25,6 +25,7 @@ import org.springframework.stereotype.Component;
 @Component
 public class GroupVmCache extends VmCache<String, AuthorizationResponse> {
     public GroupVmCache(@Value("${app.maxExpireTime:60}") int maxExpireTime, @Value("${app.maxCacheSize:1000}") int maxCacheSize) {
-        super(MathUtil.generateRandomNumberBetweenBounds(30, 60), 1000);
+        //randomizing cache TTL will reduce sudden spikes on downstream service because cache in different pods expires at different times
+        super(MathUtil.generateRandomNumberBetweenBounds(maxExpireTime/2, maxExpireTime), maxCacheSize);
     }
 }