Technical Debt has been extensively studied in software engineering, mainly to identify and measure its negative effects on the technical quality of products and processes. Recognizing that software development encompasses both technical and social dimensions, some studies have characterized social debt as the accumulation of suboptimal socio-technical decisions manifested through community smells. Similarly, User Experience Debt (UXDebt) is an emerging concept that reflects the cost of suboptimal decisions in user experience design that grow over time, making them increasingly expensive to fix. UXDebt remains under-explored despite its dual impact: it affects end-users by degrading user experience and development teams by increasing system complexity and maintenance costs.

This study examines the causes of UXDebt, particularly in its relationship to social debt and the suboptimal socio-technical decisions made during the early stages of product development. We used a mixed-method approach in two scenarios: i) when design and engineering roles collaborate during user interface design and prioritization tasks, and ii) when they prioritize backlog issues separately. Our findings reveal that process structure, unbalanced participants’ interactions, and early-stage decisions create conducive conditions for UXDebt emergence. Specifically, we identified three interaction anti-patterns and two process anti-patterns that facilitate this emergence, often occurring unconsciously within development teams.