This paper studies GrooveTransformer, a real-time rhythm generation system, through the post-phenomenological framework of variational cross-validation (VCE). By reflecting on its deployment in three different artistic contexts, we identify three distinct stability characteristics: an autonomous drum accompaniment generator, a rhythm-controlled voltage sequencer in Eurorack format, and a rhythm driver for a harmonic accompaniment system. Since versatility across diverse applications was not an initial goal of the project, we question how this multi-stability emerged. Through VCE, we identify three key factors: conditions of system invariance, interdisciplinary collaboration, and the contextual nature of development. Finally, we reflect on the feasibility of VCE as a technical method for designing digital musical instruments (DMIs), highlighting its value in revealing how technologies mediate, co-construct, and co-construct users and contexts.