Modern software-intensive systems are growing more complex, evolving continuously, and requiring extensive collaboration across diverse domains. Effective documentation and communication of architectural changes are critical to managing the development of such systems. But this task remains challenging due to constraints in time, resources, and standardized practices. This study investigates the practices and challenges related to architectural documentation and communication in the development of software-intensive systems through semi-structured interviews with architects from four partner companies. The findings reveal key challenges, including identifying stakeholders for communication, inconsistent architectural definitions across teams, and knowledge transfer issues due to differing tools and terminologies. Participants also shared their reliance on informal mechanisms and ad hoc processes to address these challenges. Insights from this study highlight the need for more structured, standardized approaches, flexible documentation methods, and improved cross-domain collaboration tools. The results provide actionable recommendations for both practitioners and researchers to enhance documentation practices, improve team alignment, and ensure the effective management of architectural changes in dynamic and large-scale software systems.