I’m getting the feeling that the router is what’s causing the problem. Can you try creating a completely new scenario (you can leave this one intact to return back to) with all the same modules EXCEPT leave out the Router module. Instead of having 17 different Shopify modules all doing basically the same thing, you would make a single Shopify module that’s more generic, i.e. it can be applied to ALL the data you wish to process.
I realize you may be using a separate module for each so that you can specify the Inventory Item ID, but using the switch function could help consolidate that into a single module. Here’s a great example of the switch function in use. It’s down towards the bottom but the whole article might give you some good insight.
Taking examples from some of my own scenarios, after the scenario is run and you check the history, is the previous module showing multiple operations like this?
Or is it all in a single array more like this? (notice the word array on the top line)
Or even just a collection? If one of the latter two as I assume, you could then use an Iterator module to split out the data in the array to multiple operations. Or if a collection, use the relevant mapping fields to cycle through each of the instances.
Definitely look to the data you’re pulling in from the previous module (I believe it’s the trigger itself) and see how Make is interpreting it. Maybe paste a screenshot of that from a previous run. From there, we may be able to give you a better idea how to reconstruct the scenario without the router and a single Shopify module.