X axis is sitting between 2 subplots


I’m having an issue where the xaxis is sitting between 2 subplots (3 subplots on the y axis, sharing one xaxis).
for a screenshot, please go here: https://github.com/plotly/plotly.js/issues/4257
How do I position that at the bottom correctly?

Also, I have tried many different combinations of the xaxis layout settings and have been unable to specify the xaxis label intervals. I would like to mark 31.5, 63, 125, 250, 500, 1k, 2k, 8k, 16k.
which layout options should I use?

Many thanks