Premiere Pro Transcription and Captions - Merge Button Disabled

Hi, I recently updated my Premiere Pro to Version 23.5.0 (Build 56) and since, whenever I generate a transcription for my projects (different projects, some created from scratch and some duplicated from existing ones), the "Merge" option in both the transcription panel and the captions panel has been disabled.

I don't know what to do to enable it again. Any help is appreciated.