Really, it's true.
I don't yet have a simple example, but just spent the last 1/2 hour
I have a figure with multiple semilogy plots. When I do
ax.set_title(title), no title appears (it will appear if I add y=0.95).
I tried various constrained_layout and many other things. But finally, I
found that some of the data had NaN. Using pandas dropna, to clean the data
presented to semilogy, NOW the title appears.