I am having the same issue. All of a sudden on June 15 Shopify started sending server side events to the Facebook Conversion API, duplicating our FB Pixel data and introducing a bunch of errors. Hoping we get some resolutions ASAP, our conversions took a big hit.
Server External ID Not Matching to Pixel External ID for ViewContent Event
Server Sending Invalid Match Key Parameters for ViewContent Event
Server Sending Invalid Match Key Parameters for AddToCart Event
AddPaymentInfo Event Missing Some Deduplication Parameters
Hi everyone, I found out what's going on here.
When Facebook updated their API a couple weeks ago, it caused us to start seeing this error. I've been told by a Shopify rep that Facebook has pushed out a fix to resolve the error. However, this error is not related to the problems we're having with missing events and poor conversions.
The same Facebook API update that caused the error also implemented additional filtering that rejects events from iOS 14.5+ users who have not opted-into tracking. This is by design.