Rogue Purchase Events Fired in GTM Server Container

[FDivecha]

For one of the clients we've set up the GTM server integration for a Shopify site. When testing tag fires, we noted a Purchase event was being received by GTM server container on ViewContent & InitiateCheckout events, even though the Purchase tag wasn't fired on the GTM web container. I've double-checked this myself, and even showed it to the FB solutions engineer for Southern Europe, and we cannot figure out how / why this is happening.

Naturally our first suspicion was Shopify, but we've even disconnected the Shopify integration, just to be sure even though Shopify was never given the server container transport URL. Unsurprisingly, the error still persists.

Happy to share details in private or via the Direct Support for CAPI. This feels more like a GTM bug than a Facebook integration bug, but I'm not sure we can get any direct support from Google on this.

[FDivecha]

(This was originally posted in the GTM Client repo by mistake. I don't believe that's being monitored, so I've reposted here. Please feel free to delete the one under the Client repo, since that's no longer used.