Custom Y6B Yaw issues

Hello, I have recently built a custom Y6B, and am having troubles with its Yaw.

The specs are

APM 2.6 FC 3.2.1 firmware
Flite Test Electrohub Frame with wooden booms for arms
6x 2213 950kv motors
10x4.5 HQ MR Props
6000mah 4S battery
25amp BLHeli ESCs with Dampened Light enabled.
Take-off weight 1.9kg with my camera hard mounted

I performed an autotune which got the pitch and roll feeling decent. When I Yaw though, it does not want to hold its altitude, or heading, especially once finished yawing. If I yaw it 360 degrees giving it full stick, it starts off yawing slow, then speeds up. Once I re-center the stick, it continues to Yaw, gradually slowing down, and ends up 45-90 degrees past the point I released the stick. I am guessing it has to do with the PIDs, but i’m not really sure where to begin with them. I have calibrated the compass multiple times, and it appears to track properly in MP. Auto Analysis shows the compass as good, mag_field interference within limits at 21.5%. The Compass and GPS combo is mounted about 7 inches above the frame. It also seems to wander left and right a little, maybe 10 degrees each direction from the heading I want. In Loiter, it makes me sweat when I yaw , because it either rises or falls, and twitches around a good bit.

Is this a usual problem with a Y6 on the default Yaw PIDs? What is a good way to tune the yaw? My previous spider quad layout with this same APM 2.6 board and compass did not have this issue. What are things I should look for in the dataflash or telemetry logs?

After a few more flights, I found the issue. It turns out the antenna for my receiver was frayed. I discovered it when the Y6 kept going into failsafe during flight. Replaced the receiver. no more odd yaw issues. I am guessing the frayed ground wire for the antenna was causing some noise.