Smart content render decision block in header menu has 0.5 second delay

Problem/Motivation

Use smart content for different menu bar A/B test with Optimizely.
The issue we have right now is: it seems that both block menu inside decision config load 0.5 second delay. It feels like kill the original entity first and then load the decision_storage.
Is there any easier way to avoid the 0.5 second delay? any twig file debug or patch I could look for?

Thanks.