If the device is not responding anymore it may have completed the update. I think the ZEN27 typically resets itself after updating, so you have to use the z-wave replace feature to join it back to the hub afterwards. You can also just pair it again but it will create a new device entry and leave a ghost node behind.
My concern is these seqno which I assume mean sequence number.
I would expect that they would go from 0 to 255 twenty-two times (5766/255). But it seems skip some numbers and double up others. For example, highlighted in yellow 198 (two times) followed by seqno: 5
Thats the Z-Wave logs? I dont look at those very often, usually it is not very useful. Not sure how the sequence numbers work exactly, but yeah I would expect it to work as you said.
Also probably was not needed to shut down all the switches, they are not usually sending out messages unless you use them, I was more thinking if you had any sensors or power meters that might be clogging up the mesh a little.