Its extremely common for Dualshock 4's to not reach that 255. One of mine is really bad, must only reach 80 or 90%.
Kind of have a funny story about that, my friend had a controller doing this but we had no idea about it. We were playing one of my GTAV races where a long jump was required and he couldn't reach a fast enough speed to make it. He got annoyed and I was very confused, I was saying to him I definitely tested it and it should be working, but he just thought my race was rubbish. A few months later he realises his controller is doing this and straight away I said "oh my god that's why you couldn't make that jump" and everyone in the group chat laughed, it had haunted me for a while. We tried the race again with him using a different controller and all was fine. I'm a good race creator!
So yeah, anyway, could be that
Kind of have a funny story about that, my friend had a controller doing this but we had no idea about it. We were playing one of my GTAV races where a long jump was required and he couldn't reach a fast enough speed to make it. He got annoyed and I was very confused, I was saying to him I definitely tested it and it should be working, but he just thought my race was rubbish. A few months later he realises his controller is doing this and straight away I said "oh my god that's why you couldn't make that jump" and everyone in the group chat laughed, it had haunted me for a while. We tried the race again with him using a different controller and all was fine. I'm a good race creator!
So yeah, anyway, could be that