I tried the same thing on my copy and it worked even when I was using AccessControl to insert records. My table is a very simple table and I am running suneido.exe standalone.
If you are running client-server, the trigger will be executing on the server side and the Inspect will not work as expected. In that case you could try using SuneidoLog, or writing to a file instead to debug your trigger.
If you are running Suneido standalone, it is possible there is something about your table that is different from the simple one that I set up. Again, writing to a file (you can use the AddFile function for that), or SuneidoLog would be a better option for debugging than using Inspect in your trigger.
I hope this helps you figure it out. If not, with a little more information we should be able to sort it out.