There are two options to get rid of that sliver that I know of:
- Change the width of your pour; a smaller value may fill in the gap, or a larger value won't make as tiny of a sliver.
- Put a 'pour keepout' there.
I manually waive the errors. In other words, when I get to a list of errors that are acceptable, I save a copy of the error report in my design folder and describe why the errors are acceptable. That way the next designer knows what violations they has to ignore. I'd much prefer a real waiver.