I’m noticing a weird issue with the Amplitude plug-in for Shopify where no [Shopify] - Purchase Item events are being fired for [Shopify] - Order Created in the case where a customer used a “fixed_amount” promo code (note: “percentage” type promo codes do not have this issue). Relevant parts of the event_properties payload from the [Shopify] - Order Created event that have led me to believe this is a problem with this sort of discount are shown in the image below.

To help troubleshoot, these are all the discount apps that are currently live on our store. Are there any documented cases with any of these apps interfering with the Amplitude plug-in’s ability to fire [Shopify] - Purchase Item events?
- DiscountYard
- Friendbuy
- Rewardify
- Bulk Discount Code Generator
Thanks in advance.