This is definitely still happening, I had success when I eliminated the datetime x when plotting the bars... then relabeled the xticks using a datetime sequence afterwards:

x_labels = np.arange(np.datetime64('start'), np.datetime64('end'), np.timedelta64(1,'M')

x = range(0,len(x_labels))

ax.bar(x, df.distance, width = 0.95)

ax.set_xticks(ticks=x, labels=x_labels, rotation=90)