XOR_experiment progress_bar problem

[MalinSpaniol]

In this experiment, I used _.flatten() and _.shuffle() in main.js views_seq:, and then want to show progress bar chunks for each of these blocks (4 in total).
Always once in the experiment, the progress bar jumps back one block and fills again. Thereofre, when the experiment is finished, only 3 out of 4 blocks are filled. The branch where this problem occurs is: https://github.com/babe-project/XOR_Experiment/tree/progress_bar_issue .