Objectives This study aims to investigate the modification patterns of post-editing(PE) in Vietnamese-to-Korean machine translation(MT) by Korean language learners at Vietnamese universities. Methods Twenty-five Korean majors at Vietnamese universities performed PE on a Vietnamese text and recorded their reasons for modifications. The 192 modifications made by the learners were analyzed based on eight error categories to identify their error recognition and correction intention. Results The results revealed that learners prioritized correcting semantic errors over morphological errors in the machine-translated texts and among semantic errors, attempts to correct clarity errors were the most common. However, some corrections deviated from the intended meaning, or introduced new errors during the correction process. Conclusions This suggests that learners need education to consider various aspects beyond simply replacing awkward or incorrect expressions when recognizing and correcting errors. Furthermore, machine translation er-rors frequently necessitate more comprehensive revisions than merely addressing individual aspects. Therefore, it is necessary to provide detailed and step-by-step education by providing post-editing guidelines so that learn-ers can improve by considering various aspects.