Upgraded last night to 2.3.6.144. Did a soft reset just prior to the upgrade, as I hadn't done one in almost a year and wanted to avoid issues. This morning most of my routines went off fine, with the except of 2 z-wave plugs( Zooz & Inovelli) so I manually attempted to turn them off, got nothing. Checked z-wave details, no ghosts and both devices had the proper info in their rows. My z-wave had been pretty flawless over the last 1+ years. So I'm not certain this is upgrade related but put in out there in case anyone else has a similar experience. I did notice my hub memory is much lower than it had been in the past, but typically Zigbee is the first to crash if memory issues, and my Zigbee was fine.
Did a Hub shutdown and power pull for 30 seconds and everything, including z-wave is back and functional. I understand there likely was zero Z-wave changes in this update, but don't know if other update changes made could influence Z-wave.
After a big upgrade the first reboot can chew up some memory, due to maintenance / cleanup stuff. If that happens and is a concern, wait 10 minutes and do another reboot which should get you back to normal. The update to 2.3.6 should actually get you more free mem with a slower decline, at least that's what a lot of the beta testers were seeing.
That's not the case for 99.99% of users. There are some, like @Rxich with a mix of custom drivers and apps that that could run into problems, not necessary related to the update itself. The good news is that after the hub settled, @Rxich's hub appears to be running smooth.
@Rxich let us know if you continue to have any problems.
I see this issue sometimes with upgrades. A soft reset doesn't fix it. The z-wave radio is minorly corrupt so when the new platform comes online z-wave doesn't work. The shutdown, unplug for a min to clear the z-wave radio, power backup works. This isn't a fault of the upgraded platform, it's just something in the radio. The z-wave and zigbee stack hasn't been played with in a while so unlikely issues arise from platform upgrades like that. As you found clearing the radio fixes it.