This paper presents results from a randomized trial of a nudge intervention designed to encourage and enhance virtual student support. During the 2019-20 school year, randomly selected mentors in a school-based mentoring program received monthly reminders with tips for communicating with youth via text, email, and phone. Unexpectedly, the results showed that although the informational reminders did not impact the frequency of mentors' outreach, they reduced the rate at which students reached out and responded to their mentors. Moreover, and possibly as a consequence, mentors who received the intervention felt less connected to students and less satisfied with their mentoring relationships, and treated students gained less from the mentoring program as a whole in terms of their personal and attitudinal growth. This study's findings add an important nuance to the evidence on how behavioral interventions in educational contexts operate. Although past studies find that reminder nudges can support individuals' engagement in discrete tasks, this evidence suggests that prescribing relational practices may be less effective. Thus, mentor supports must be carefully designed in order to yield the intended benefits for students.