I think we can all guess what happened, but if you want a likely explanation…
Results of this study demonstrated a relatively modest effect of that ruling in reducing weekly head impact burden during the preseason (− 2.2%) and the unanticipated effect of increasing the total head impact burden by over 25% across the entire preseason. This was likely attributable to increased contact intensity (impacts per hour) during the 2017 preseason, resulting in a greater number of preseason head impacts over the same number of preseason team contact practice sessions.
In other words, coaches compensated for the elimination of two-a-days by amping up the intensity of the practices they had. Hey, nobody saw that coming, right?
The great thing about this is that the litigation threat isn’t going away, so the NCAA is going to have to take another stab at fixing the problem. Lather, rinse and repeat for the win!