I’ve successfully made a disc once without any problems, but the subsequent discs have had playback problems when I skip through the chapters to check them.

9 times out of 10 the problem is with the very last Title on the disc.

By going into the Title properties I changed the timecodes for the chapters so they break where I’d like them to. I followed the required format. For example my chapter timecodes are: 0:00,1:24,14:10,25:04,:25:25

To make the other discs I duplicated disc one's dvds file and removed, then re-added the different video files changing their timecodes as well.

The dvd is NTSC and even though the videos are PAL I made sure they’re NTSC in DVDStyler.

I’m using version 2.5 on Mac OS 10.8.5.

I’ve tried creating a brand new disc; same problem.
I’ve tried uninstalling (preference files and all) and reinstalling DVDStyler; problem persists.
I’ve tried removing all the videos and re-adding; same.
I’ve tried re-adding without changing the default chapters; same.
I've tried splitting the video into individual videos for each chapter and adding the videos as chapters; same.

I don’t know what’s going on...