TIP: Resolving Catalina/Mojave Accessibility/Security Permissions Issues

After upgrading to Catalina (OS 10.15.5), I tried adapting this script:
Make Team Calendars Macro by @peternlewis
Encountered a couple of problems with the AppleScript in that example macro:

  1. It creates a calendar event without an error message but the event is not visible in the Calendar app even after reloading calendars. A separate line of script in Script Editor is able to retrieve the event and read all of its properties, so I know it is there somewhere.
  2. The script throws an error when trying to
    make new display alarm
    so the line had to be disabled. The error message showed NSDetailedErrors. Haven't seen this before in AppleScript.

AppleScript in my Catalina installation seems to be responding differently to Calendar commands.

KM and Engine permissions are working fine, but I don't know whether Calendar has new permission issues.
Could be new command syntax, but I could find no documentation or messages.
Anyone able to offer insight?
Thanks