Oh thanks for the reminder, long story short, I went to post it after I recorded but it was during the switch to to Gitea so I had troubles and thought I would get back to it later. Production got in the way and I didn't.
I originally posted this bug a long time ago but was told it was "intended behaviour", and there was a workaround.
At the time of recording there was no way to make it show up to the frame you specified (always n -1)
In Blender 3.5 it still shows n-1, however there has now been a new "manual range" option added. So you can do a work around by manually changing the range to n+1.....which will actually show you up to n.
It would be nice if it included that last frame by default.
If you could bring it up with the Animation and Rigging module that would be great :)