Hi PP1965,
unfortunately there’s nothing we can do to eliminate this issue right now.
We’re in contact with apple and we hope that they will provide soon a fix for Logic or tell us what we have to change in our plugins to solve the problem.
A possible workaround from the LogicProHelp forum is perhaps this one:
Finally I created a new admin user, started Logic and after the validation of the plugins I could create a new empty project with an instrument track. And YES, the Steinberg menu was there, I could use it again.