Sustaining architecture stability in incremental software development is an important aim for software engineers. Traceability mechanisms can be used to assess and predict architecture stability based on recorded information of early software artefacts. However, there is little empirical knowledge on whether traceability of stakeholders' concerns can assist the identification of architecture instabilities. This paper reports on a first exploratory study that analyses the effectiveness of concern traces for architecture stability assessment. We investigate to what extent properties of concern traces, such as their shapes, are correlated with architectural instabilities. Our analysis is based on eight releases implementing two versions of a software product line for handling mobile media.