One of the promises of edu-metaverse is that it can provide a virtual environment that can enable us to engage in learning activities that are similar to or on par with reality. Coupled with the digital enhancement that can be introduced in a virtual environment, learning in an edu-metaverse has been expected to bring novel learning experiences to students. However, despite its captivating outcome, it seems there is limited adoption of edu-metaverse for practical learning currently. We believe this can be attributed to the fact that there is a lack of investigation into learners' behavior given a social learning environment. This lack of investigation is critical, as without behavioral insight, it hinders the development of education material and the direction of an edu-metaverse.This paper aims to provide insights into learner behavior in edu-metaverse by conducting a focused pilot study. Particularly, we investigate the learners' behavior when drawing mind maps in the metaverse aided by the embedded knowledge graph. Compared to Zoom, a typical video conferencing and remote collaboration platform, it seems that users are more involved in learning activities, and the co-presence seems to assist in engagement so that they are more willing to contribute to the learning task collaboratively. Our work also provides insight into the interaction and learning activity design for edu-metaverse, particularly when mind maps are involved.