In Inventor, the title block and sheet border are treated as separate objects (so you can do things like swap out title blocks or change sheet sizes without breaking the border).
Since you are bringing one object through and calling it a title block, Inventor will place it slightly offset from the bottom right corner of the sheet. It choses the position base on the border - but in this case, you don't have one.
To define the offset, you need a drawing border. You can create a small fake border for the purpose of locating the title block: In the "Drawing Resources" folder in the browser, create a new border. Draw two lines to represent the corner of the sheet - you'll find a point you can constrain/dimension to right on the edge of the sheet - see below.

Insert the border, then insert the title block. You should find the bottom-right corner of the title block geometry lands on your mark.
Peter