I have openhabianpi installed. (openHABian hassle-free openHAB Setup)
I noticed that when the dtoverlay=pi3-miniuart is in the /boot/config.txt will stop z-wave from working.
My config.txt is as follows:
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. lines before
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# Disable the PI3 bluetooth and wifi and remove the miniuart
dtoverlay=pi3-disable-bt
dtoverlay=pi3-disable-wifi
#dtoverlay=pi3-miniuart-bt