I am having the same issue as Matthew, it seems like the Symbol layer drawing is acting up in Pro. In this particular screenshot, wouldn't the Group_2 Arterial Minor brown line (which should be a casing) draw over the beige line? The same with the "LOCAL" black line symbol over the white line symbol?
I am missing something?
Sometimes after making changes in the symbol layer drawing, the features will also just disappear, only coming back after closing out ArcGIS Pro. Then, after re-opening, the symbol layer drawing will be back to if you just started working on it