If you set the label to "resize freely", then it will adjust its width and height accordingly.
You need to use Advanced type anchors if you are mixing anchors and resizeable labels, and set only certain sides to be anchored.
For example to anchor a ResizeFreely label to the top left corner, change its pivot to top-left, set anchors to "Advanced", and only choose the top and left anchors. Don't set bottom and right.