Adding symbol GND to F09-S would exceed the minimum number of pads (11) availble in package variant V
This is a device I copied directly from Eagle 5.7.0's library (con-subd.lbr) because in my design only one of the two shield lugs were being wired. I was only conecting to 10/11 pads, but adding annother GND symbol increasing the symbol count to 11 actually exceeded the pad limit of 11.
The connect window shows that there are infact 11 pins already defined, including G1 and G2. Typing show G1 in the command line is unsuccessful, therefore these pins must be defined within a symbol.
A look at the symbol (GND.sym) appears to illustrate a single pin, right clicking and selecting properties reveals G1, a wire and a circle. G2 must be nearby, and show G2 in the command line reveals that it is hidden under G1, backwards!
So in the schematic editor by using the wire tool and clicking on the GND symbol only the top pin was engaged. Had I run Eagle's Electrical Rule Check it would have produced a warning that would have confused me and prompted the same response.
This is a common symbol in Eagle's library, let's hope that 5.9.0 has it documented.
EDIT: typo, G2 and G1 transposed.