I rarely have that issue, but I remember a few  cutting off early, no issues with the start point. I usually generate the transcript and let it fully load prior to initiating the creation of a clip, maybe that helps (I have fountain premium and use the beta version of the app)
Links to my playlists + clips + tunes:
https://nostree.me/debasedghost@vlt.ge 

 Thanks for the advice. I don't have premium.  I'll switch to that