For the online top up to be stored, you have to tag on somewhere within 60 days. If not, you have to ask AT to either reactivate the top up, or refund the money.
In other words, as long as you activate the card, the funds will be on it - for up to six years, as AT had extended that from two. Activated top ups don't expire after 60 days.
AT tells me it emails HOP card users ahead of the 60-day expiry, and using a machine to add funds - or auto top ups - means you're not subject to the time limit because the funds will be registered on the card at the time of purchase.
If you're not going to use the top up straightaway, you can also tell AT when you intend to travel with your HOP card, and the funds should be ready then (I'd be curious to hear if anyone has tried this).
That's the problem then: the stored value on the cards is managed via the tag-on terminals and electronic gates.
There's no way to directly add the online top up to the cards without looking up and copying over information from the tag-on terminals that is refreshed daily, and which says a HOP user has added funds.
As anyone who designs any kind of electronic transaction system knows, they have to be fast or users will start screaming at you.
Since speed is of the essence, AT and Thales decided to skip inactive cards from the daily action list that's loaded on to the tag on terminals, to save time and not look them up.
Good luck, though, to AT in trying to explain the technical niceties of the HOP integrated ticketing system to someone who knows their card has money on it, but missed the not-so-obvious 60-day deadline to activate the top up and can't get on the bus, train or ferry.
The issue boils down to mismanaging user expectations. If you put money on a stored value card, it needs to happen automatically without users having to take two steps to complete the transaction.
We're talking about what's very much an edge case: AT says 97.4 per cent of cards topped up online are activated within 60 days, and only 15 per cent of HOP users in total top up online.
It'd be silly to be too harsh with AT over this because they've done their level best to manage it, and many other stored value cards from public transport providers around the world have the same limitation.
Which isn't to say AT and Thales shouldn't come up with a fix. Getting a black eye from the public over a technology limitation they can't understand is never worth it.
Time for a tech upgrade for AT, so travellers aren't caught on the HOP again.