Thank you Techman. I resolved this problem by disconnecting the lock from the Ultraloq wifi bridge and then including it again even though the IoX node was still listed. I included as a new node and I was then able to 'Remove Fail Node' on the old node. I think that using the Ultraloq wifi bridge as well as Zwave was creating problems.
Not too many posts on this forum regarding Ultraloq U-bolt locks, so I'll add some info here in case someone else comes up with issues. I like these locks quite a bit although I don't have anything to compare them with. They seem to be solidly built. I wouldn't spend money on the fingerprint feature because it just doesn't work reliably. I was having some quirky behaviors with my 2 locks, so I disconnected both of them from their wifi bridge (each bridge only accommodates a single lock) and only use the UD Mobile app for remote status and activation and zwave inclusion/exclusion. I still can get full lock status with the Ultraloq app using bluetooth; gives me all the other features like access logs, firmware version, etc. Battery life may be an issue; some users report only 4-8 weeks of life using rechargeable NiMH.
The root problem causing eisy to crash was that it was in AP mode. I should have been able to diagnose that myself. I have other PG3 licensing problems, probably also caused by me during migration, but PG3 and eisy are now stable.
I can't say enough good things about UDI's technical support. I have never experienced such a high level of responsiveness and capability. Michel gave me his time for free but I chose to run a charge through for an hour of programming and support. I suggest that anyone who can afford to do so, please consider paying for support when your issue is clearly not a bug.
Phil G's post in Zwave exclusion error was marked as the answer