multisites sets up view tables for the following tables:

jev_users
jevents_categories
jevents_exception
jevents_icsfile
jevents_repbyday
jevents_repitition
jevents_rrule
jevents_vevdetail
jevents_vevent


When you create a calendar category using the parents jevents admin tool, it only stores the category color and an id number in the table "jevent_categories". It actually stores most of the information for the category in the "categories" table that the Joomla core uses and references it by the id number. Note: Using the admin tol, you can't see these jevents categories-you must use your sql editor (phpMyAdmin) to view the table to see that data.

For this reason, you can never edit calendar categories after the slaves are built initially unless you want to manually replicate the rows into the children's "categories" tables

Thank you for the explaination.
I don't see any short term soluton to that.
So I will remove the JEvents as part of the sharing extensions.