This research explores the impact of the unforeseen global crisis on education and assessment practices, investigating plagiarism rates through a comprehensive analysis of 25,864 written assignments from 42 academic institutions in 2019, 2020, and 2023 before, during, and after crises, such as pandemics. Utilising the theory of planned behaviour comparing undergraduate plagiarism rates before, during, and after the COVID-19 pandemic using an automated plagiarism detection tool (Originality). The comparison traverses academic fields, disciplines, institutional rankings, and written language assessments. Contextualising this phenomenon is crucial for a comprehensive understanding and targeted interventions against undesirable behaviour. The results show that before and after COVID-19, plagiarism rates were similar, while during COVID-19, plagiarism rates augmented. Furthermore, assignments written in English contained higher plagiarism rates than those in Arabic and Hebrew. We discuss post-pandemic plagiarism rates bounce-back in higher education on the one hand and concern about artificial intelligence writing tools on the other hand. We also discuss plagiarism among multilingual students. The study concludes with practical implications and suggestions for future research in the evolving landscape of academic integrity.