Backlog coupling is when work defined in one product backlog depends on work from one or more other product backlogs to be completed before the work can be completed. While some coupling is inevitable, excessive coupling between backlogs causes productivity and responsiveness to suffer and usually indicates a team topology or architectural problem. When unaddressed, backlog coupling damages a team's ability to account for outcomes, and ultimately erodes motivation and leads to apathy because it becomes easy to shift blame and give up on ideas to improve.
Backlog coupling resources
Broader Topics Related to Backlog Coupling
Resources for Project Management