transcript stops tracking when I'm playing in the timeline

Working on a friends macbookpro... it's about 1 year old and pretty tricked out...   at some point as I'm working on the edit the transcript stops tracking as I'm playing the timeline...  Was happening repeatedly today.  If I reset the preferences it would work again for a while...  Is there something I'm missing?  Or should I maybe do a clean install...  Will be back out there on Thursday and will make sure we've got the latest version (definitely 2024) installed...    Just wondering if I'm missing something obvious

Thanks as always.  Today was concentrating on getting as much editing done as possible... so didn't want to spend a lot of time troubleshooting.    Will report back...