Task delay is pervasive in interdependent work, yet its meaning and consequences remain theoretically contested. Drawing on qualitative interviews with 24 undergraduate students working in highly interdependent project teams, this study examines how team members interpret task delay over time and how emergent temporal leadership regulates the resulting coordination and relational challenges. We show that delay is not uniformly perceived and experienced as self-regulatory failure; instead, team members actively distinguish strategic, agentic delay from chronic procrastination using cues such as trust, past performance, and communication behavior. These attributional judgments shape whether temporal differences generate tolerance or escalate into anxiety and conflict. We further identify emergent temporal leadership as a critical regulatory mechanism, enacted through a flexible repertoire that treats time as structure, resource, and relational process. By theorizing delay as an ambiguous social signal and temporal regulation as an ongoing interpretive cycle, this study extends research on procrastination, temporal diversity, and temporal leadership, and offers new insight into how teams sustain coordination and relationships under temporal heterogeneity.