Loiter Mode: Drone Drifts Aggressively After Releasing Sticks to Neutral — Regression in 4.8.0dev (Works Fine on 4.6)

## Bug Report ### Issue details In Loiter mode, after flying for a certain period of time, when the RC joysticks are released to center (neutral position), the drone exhibits aggressive movements and drifts in a random direction instead of holding position. The issue is a regression introduced in 4.8.0dev; the same hardware and configuration works correctly on 4.6. **Steps to reproduce:** 1. Arm the vehicle and take off in Loiter mode 2. Fly for a certain period of time 3. Release both joysticks to neutral/center 4. Drone begins aggressive movement and drifts in one direction instead of holding position **Expected behavior:** Drone should hold its position when sticks are centered in Loiter mode. **Actual behavior:** Drone exhibits aggressive uncommanded movement and drifts in a fixed direction. **Regression:** Issue is not present on 4.6. Confirmed working correctly on 4.6 with identical hardware and configuration. **Version** ArduCopter 4.8.0dev (master branch) **Platform** [ ] All [ ] AntennaTracker [X] Copter [ ] Plane [ ] Rover [ ] Submarine **Airframe type** Quadcopter **Hardware type** Pixhawk V6X-based custom carrier board **Logs** Two logs are provided from the exact same hardware and configuration — only the firmware version differs: - 4.6 [this link](https://drive.google.com/file/d/1SgrSsFT9Nh2pDEhrXoHBRrWZtbDRndSy/view?usp=sharing) — Normal Loiter behavior, drone holds position when sticks are centered. - 4.8.0dev [this log](https://drive.google.com/file/d/1DVnu6CXiMEYzWZ9C4gwxMsssf9BdilMJ/view?usp=sharing) Aggressive uncommanded movement and drift observed when sticks are released to neutral in Loiter mode.