In this workflow, the merge node is working with just the first output received (separated in groups of 8) in the item Lists instead of 74 items to be analyzed it’s doing just with 8.
The Merge-Node will execute every time it receives data on the first input. In your above example the IF Node runs once and it sends the data into the Merge Node. The Item Lists node runs 8x (as there is this looping going on). Meaning the Merge Node will just execute 1x using the data from the IF node and from the first run of the Item Lists node.
If you want to make it work as you want it to work you have to make sure that there there is only one node run for the node on input 1 and input 2.