It fails because the setup that worked fine at launch was never revisited as the business changed shape. A design choice that made sense with one warehouse and one channel quietly turns into a liability once new locations, curbside pickup, a rewards program, or negotiated customer pricing enter the picture, and instead of stepping back, teams just keep bolting more onto the same original plumbing. Early on, the needs are simple: get catalog items, orders, customer records, and stock counts flowing between systems. Problems surface later, once the business has outgrown that pattern and nobody has stopped to ask whether it still fits. Below are eight patterns that repeatedly cause friction in Shopify and Adobe Commerce deployments tied to F&O, along with what tends to work better.