Cannot ping ready-but-unavailable abilities (Kat R, Eve Q)

With the new ping system, you can ping to indicate the current cooldown of your abilities or if they are ready.

However, if you have an ability that is only available for use under certain circumstances, such as Katarina's ultimate or Eve's Q (which both need a nearby enemy), you cannot ping to indicate that the ability is ready for use unless the spell is currently available for use (e.g. there is a nearby target.) Note that trying to ping on it will count towards your ping limit, even though it does nothing (you will see a warning that you cannot send any more pings if you spam it.)

This issue can be easily reproduced by simply selecting Eve in a custom game. You will not be able to ping her Q, but if you go near a monster in the jungle then the ping will work.