The 2nd title of travel Z2 will be deducted only when the time defined for the 1st title expires.
For a course between Trindade and Aeroporto, the correct title to be used is a Z4.
So, if you use a Z2 title to travel between Trindade (C1) and Senhora da Hora (C2) (maximum range you can use the Z2, since you have already crossed two zones and are on the border of the third), it hardly passed around 15 minutes. In other words, a Z2 allows you to travel for one hour, only when that one expires you can validate the next title you have in your card, so, they are still lacking 45 minutes to finish the validity of the 1st title initially validated in Trindade.
So, if you try to validate the 2nd title Z2 to follow up to Aeroporto, it will not be deducted and you will be travelling illegal. The 2nd Z2 title will only be deducted if it had already passed 1h after the 1st validation. If you don’t want to wait, you can validate another card loaded with another Z2 title, or just load your card with a Z4 to begin with.