Working with a customer who has the parent item of a matrix subitem is showing in search results when I search for transaction lines (item fulfillment). I can't reproduce that behavior in my test account. So far the only workaround I've found to exclude these is to add the following filter expression:

["appliedtotransaction.linesequencenumber", "isnotempty", []]

Anyone have experience with this? Is this the right way to handle this?

Maybe you can refer back to the item fields : matrix and Itemmatrixchild So "isnot" matrix OR "is" matrixchild

Thanks! Makes sense. Safe to assume you can never have a matrix item (parent) on a fulfillment (only a matrix children)?

What do you mean it has the child item there twice? Where? You see the same item on more than one line where it only appears once on the item sublist? 🤔 Are you excluding other line types such as shipping / tax /discount, not sure that's your issue but maybe something to look at.