pressing "stop tracking" at 0 AP doesn't work

[squib]

When you have 0 AP and are currently under the influence of the tracking status effect, pressing the "stop tracking" button yields the following message:

You do not have enough action points to act!

If i recall correctly the button costs 0 AP, so shouldn't it work at 0 AP? and if it costs 1 AP to end a tracking session then why? That don't make no sense either!