Thanks to a heads up in this post on Steve Bennett's blog, I am now aware that the default setting for island detection has been changed from Normal to Outer, as can be seen on the Hatch Creation contextual ribbon tab, on the flyout of the Options panel, on the Island Detection drop down list.
Outer will only hatch the outermost area, ignoring any "island" areas.
The former default value, Normal, will hatch the outer area, skip the "first" island but then hatch a "second," nested island, and alternate the hatching of additional nested islands, if any.
The default value for island detection is stored in each drawing, and can be changed in several different ways. While in the HATCH or BHATCH command, on the Hatch Creation tab, or on the Hatch Editor contextual ribbon tab when selecting a Hatch object, you can expand the Options panel and use the Island Detection drop down list to choose your preferred value.You can also use the Hatch and Gradient dialog, accessed while in the HATCH or BHATCH command by using the seTtings option or by clicking on the Hatch Settings tool on the Options panel.On first use, the Hatch and Gradient dialog will be collapsed, and the Island Detection options will not be visible.Click on the arrow icon in the lower right corner to expand the dialog and expose the Island Detection area.To set the value directly, set the value of the HPISLANDDETECTION System Variable as desired:
0 = Normal
1 = Outer
2 = Ignore
Reset the default value in your template file(s) if you want the initial value in new files to be something other than Outer.