If your account matured since May and you let it roll over automatically you will get 2.25pc on the new term and that is what will display on online banking. You should have got 2.75 on the old term.
Imagine a fair few customers will do this despite the rate drops - good way for banks to make these term deposits "sticky". But PTSB allow you to access your money for an interest penalty, whereas with AIB, even on an automatic rollover, you'll wait until end of term, no matter what.