Webhook event validation issues

[mjecommerce]

I'm the Partner developer and now is developing the webhook listner for receiving the webhook events.

I found that some events(sand box)'s  headinfos are lost  ( example : PAYPAL-CERT-URL )

That maks my validation failed and throw PayPalRESTException.

The event id is:
"id":"WH-1AJ22404AX090980H-7EV87783HM8992745"
"id":"WH-9LS19234YX088240X-3CB95636NH583702F"

Could you find out what cause this issue.
Thx.