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.
Hoosier Daddy's post in Eisy crashes frequently was marked as the answer