"The record type [identifier=SYSTEM_RECORD_TYPE_USER] does not exist, has been deleted, or you do not have sufficient privileges to access its data":

This is an expected behavior since a long time ago.  Basically the record type is configured to only allow activated entries to be shown by default, so if you have a related action to deactivate an entry, trying to send the user back to the record page afterwards will always cause this error message to pop up.  Basically the best recommended way to circumvent this is to have the user land on a task after the deactivation has finished, which they have to click away from (i.e. no "submit" button leading to the end node); that or it could have a link back to the record type or site parent page, depending on what you prefer.

This is an expected behavior since a long time ago.  Basically the record type is configured to only allow activated entries to be shown by default, so if you have a related action to deactivate an entry, trying to send the user back to the record page afterwards will always cause this error message to pop up.  Basically the best recommended way to circumvent this is to have the user land on a task after the deactivation has finished, which they have to click away from (i.e. no "submit" button leading to the end node); that or it could have a link back to the record type or site parent page, depending on what you prefer.