Precursor Tablets Not Affecting Correct Quantity of Maps

I socketed a breach precursor tablet tonight that affected 10 maps, in an area I was already working in. It came up with the message that the tablet could not affect 10 maps as there weren't enough maps to target in the radius.
I then went to socket a 9 map breach tablet which went ahead without a hitch. However, a map within the radius of the tower remained completely bare.
Essentially, this precursor should have affected every remaining map, yet there is a map still (well) within the radius completely bare, with no breach.