I have set up two of my multicopters both with the APM 2.5, one is a Hexa and the other a quad.
Hexa is working fine. no problems there.
Quad is doing something strange, hovers good and all controls responsive pitch/roll and throttle work fine until you give yaw!
once you start using the yaw in ether direction, all controls switch!! pitch becomes roll and roll becomes pitch with stick positions reversed!!!