Several players have reported on ResetEra and Reddit about faulty adaptive triggers on their PlayStation 5 DualSense controllers. The cause, which is being attributed to a dislodged or broken spring in the mechanism, can be temporarily fixed, but the best resort is to opt for a warranty claim.
https://www.notebookcheck.net/Game-changing-PlayStation-5-DualSense-controller-s-adaptive-triggers-reportedly-suffering-from-malfunctioning-springs.512385.0.html