This scanning/inspection message warns you that the X-position of some textboxes are negative.
In the example below, the selected textbox has an X-position of -5mm, which would cause the present message to be issued.
Note that this message is only issued for textboxes (ie. objects that contain tokens or text that could be Sara'ed).
If you need some color to bleed off the page, then you should set the box contents to None, as shown in the image below, as this message will only be generated for boxes whose content is set to Text.
If the current textbox will be replaced by an image, using any one of the image tokens, use the ALLOW_TEXT_BLEED token to suppress the present scanning warning.