The worldwide COVID-19 pandemic has only intensified the rapid evolution of telehealth, pushing demand for mobile applications through the roof to help deliver remote healthcare services. In this paper, we investigate the delicate issues encountered in telehealth feature testing focusing on functional requirements as well security and usability requirements with their mobile applications. In this review, we cover our feedback and observations by extracting the key points from reviewed literature as well as case studies; these specifically targeted areas encompass issues such seamless video consultations, data security assurance and provision of good User Experience (UX). To solve these issues we recommend good solutions such as automation tests, penetration testing and user experience (UX) test. These results suggest best practices and novel methods to secure telehealth applications so that they meet the standards for offering medical care. With these insights presented, developers, testers and stakeholders are expected to embrace the challenges of telehealth app testing with a sharper knowledge-edge in hand towards improving digital health services through effective testing.