Problems with cfdemSolverIB tutorial case

Hi Everybody,
Recently I have found the chance to work with the IBM solver in the CFDEM, and tried to run the twoSpheresGlowinskiMPI case. After plotting the results, I found out that there are some discrepancies between the particles motion obtained by the solver and the results that are presented in Hager et al. (Parallel Resolved Open Source CFD-DEM: Method, Validation, and Application). These discrepancies are specifically related to the Drafting, kissing and tumbling phenomena in the channel, which cannot be found from running the tutorial case. Indeed, tutorial is just simulating the motion of two particles in a straight line, without no irregularity in the motion. In the attachment, you can found the differences between tutorial time steps and paper. I hope you can help me to understand what is the problem with the tutorial. Thanks in advance.
Mohammad