I've prepared a small demo project with 4 tracks (slides and title) to demonstrate the problem. 

Reproducible: Always

Steps to Reproduce:
Use attached project.
1. Prepare 3 tracks to composite
2. Preapre a background track
3. add composite transitions and composite on background track.
4. switch playback to GPU and render.

Actual Results:  
clip renders like Dissolve transition https://youtu.be/TUglN9FPoTk


Expected Results:  
switch playback to CPU in kdenlive setting and render. Clip renders as expected: http://www.youtube.com/watch?v=jUKjf9kvSp0