I know I’m not the first person to find this happening, but here’s an example of why you should be particularly wary about the Myki web site.
The actual Pass expiry date, which is correctly recorded on the card and displayed on the scanners, is Friday the 14th of May (or to be precise, 3am on Saturday the 15th).
The other incorrect detail is the Myki Money balance, which is actually $14.06 — the web site can see the relevant travel history, but hasn’t figured out that a quick jaunt down to Pakenham last week cost another $2.02. Again, this is correctly displayed on the scanners. It’s just the web site that’s stuffed.