In java 8 from b113 (earlier also) I found bug in TableView.
When ColumnResizePolicy is setted to CONSTRAINED_RESIZE_POLICY and table have data that is not fit in available tableview's height (vertical scroll is visible) then headers have improper width - but only when TableView is not focused. When TableView get focus then headers are getting proper width.

TableView before get focus:
http://imageshack.us/a/img841/6853/j9u9.png

TableView after:
http://imageshack.us/a/img43/922/169f.png

I have also created thread in Oracle forum that is explaining bug and you can get example app source code from this place: https://forums.oracle.com/message/11251219#11251219