Hi.
You might find your issue lies with the Book type of the disc being created.
In most cases when you burn a DVD it is created with a book tpye called DVD+R or DVD+RW or normal. Basically a PC friendly format. Some DVD players have problems reading these discs and hence stop playing a DL disc when it reaches the layer transition.
In past versions of Studio I used a 3rd party disc burner such as DVD Dycrpyter, DVD Shrink or Nero to burn the actual image to disc. These bits of software (amongst others) allow you to set the book type to DVD-ROM which is a DVD player friendly format. You might find that the DL discs will play with this book tpye set.
However, I am now finding with Pinnacle 12 that the Video_ts folders or ISO images are no longer compatible with any software I normally burn discs with.