2.0 OSSM failed in switching bookinfo productpage rating reviews and returns random python flask WSGI error page

Build info:
OCP 4.5.5
OSSM latest-2.0-qe
bookinfo: https://github.com/maistra/istio/blob/maistra-2.0/samples/bookinfo/platform/kube/bookinfo.yaml
samples: https://github.com/maistra/istio/tree/maistra-2.0/samples

How to reproduce :
1. Install SMCP 2.0 on OCP 4.5.5
2. Deploy a bookinfo sample app
3. refresh bookinfo productpage and get around 10% of 500 error response page
Refresh productpage and see random error page:

• 
  simplejson.errors.JSONDecodeError
•  

• 
  simplejson.errors.JSONDecodeError: Expecting value: line 1 column 1 (char 0)