Was playing through a fight and pulled R2 to throw a spear. Nothing happened. Pulled it again. Nothing. Then the character just kept throwing on its own, over and over, without me touching anything. My first thought was honestly "great, controller's dead," and I spent about ten minutes assuming I'd need a new one before I actually sat down and figured out what was going on.
Turns out there are two completely different things that get called "stuck trigger," and they need opposite fixes. Mixing them up is why so many people end up buying a replacement controller they didn't need.
The first kind is mechanical. You drop the controller, or it's just old, and the actual physical spring inside R2 or L2 snaps or slips out of place. The trigger feels loose, doesn't spring back, or just sits there limp.
The second kind, which is what happened to me, isn't mechanical at all. It's the adaptive trigger motor misreading its own resistance state and getting stuck thinking it's still being held down, even after your finger is off it. The trigger feels physically fine when you press it with your hand. The problem is what the console thinks is happening, not what's actually happening.
how I figured out which one I had
Pressed R2 with the controller off the console, just holding it in my hand. Felt completely normal, moved and sprang back exactly like it should. If it had felt loose or grindy that would've pointed to the spring. It didn't, so I ruled that out pretty quickly.
Next I turned off adaptive triggers entirely. PS5 Settings, Accessories, Controllers, and there's a toggle for trigger effect intensity, set it to Off instead of the default. Went back into the game. Trigger worked fine, no phantom input, nothing.
So it wasn't broken. The motor that creates resistance had gotten into a bad state and the fix was turning the feature off and back on, not opening the controller with a screwdriver like I'd already been dreading.
if turning it off doesn't fix it
This is the part most guides skip, because most guides assume one cause and stop there. If disabling adaptive triggers doesn't clear the phantom input, or if the trigger genuinely feels loose or unresponsive by hand, you're probably dealing with the mechanical version after all, and no setting is going to fix a physically snapped spring.
A few things worth trying before assuming it's the spring:
Restart the console fully, not sleep mode, an actual power cycle. This resets whatever state the trigger motor firmware got stuck in.
Update the controller firmware if there's one pending. Go through the same Accessories menu, select your controller, and check for updates.
Reset the controller itself using the small pinhole button on the back, near the L2 trigger. Takes about five seconds with a paperclip.
None of these worked for a genuinely snapped spring in my case last year with an older controller, for what it's worth, and I ended up just replacing that one. But they're worth ten minutes before you write the controller off.
the part where I actually confirmed it
I didn't fully trust "feels fine now" as an answer, mostly because the whole problem in the first place was the console reporting something that wasn't physically true. So I ran the trigger through our PS5 controller test and watched the actual analog reading while pulling it through the full range and letting go. It dropped straight back to zero every time. That's the number that actually matters, not how it "feels." The whole issue in the first place was feel and reported state disagreeing with each other, so trusting feel alone felt like the wrong way to close the loop.
If you're dealing with this and disabling adaptive triggers seemed to fix it, I'd genuinely check the reading afterward rather than trusting it based on one match going fine. A trigger that's intermittently misreading might work for twenty minutes and then do it again.
the annoying thing nobody tells you
Even after this fixed itself, I turned adaptive triggers back on the next day because I actually like the feature in most games, and it hasn't happened again since. So this wasn't a permanent hardware failure waiting to happen, it was a one time glitch in how the motor state got tracked. If it starts happening repeatedly, multiple times a week, that's a different story and probably means the motor itself is degrading, not just a one off firmware hiccup. One incident isn't a pattern. Ten in a week is.