

But I’ve previously encountered multiple cases of people complaining headphones not being able to match the advertised battery life – and the reason ended up being either too old a phone (meaning it lacks the newer codecs and versions for Bluetooth), or some bug in pairing leading to using the wrong codecs and/or protocol
Yep, I don’t think the A55 is the culprit either – just outlined the reasoning behind that. Sometimes pairing also gets things wrong which leads to the headphones using an older protocol version.
But that doesn’t seem to be the case as it’s using SSC, at this point I’d also just guess it’s a bad battery. You can try pairing them again but I wouldn’t be surprised if it doesn’t help. Still, couldn’t really hurt to try.