Yaw change in loiter

Hi Folks,

I updated to 3.1.3 this evening and went for a quick spin. I was actually testing my flight time from my battery packs so I spent most of the time in loiter - it didn’t seem as stable as it used to be and the yaw direction changed a number of times but about 45 degrees, usually in a counter clockwise direction but sometimes it went clockwise. There was some light wind out but nothing that significant. It’s a hexa with an apm 2.6, 3dr power module and power distribution, external compass and gps, hengli 880kv motors and 30A afro escs. I have my gps isolated on a stalk on one of my arms.

I’ve added the flight logs for the flight .
[attachment=0]2014-04-23 19-39-28_2.log[/attachment]


I cannot usefully diagnose anything without MAG logging enabled. Please add 8192 to LOG_BITMASK (set it to 9150) to keep your current log configuration and add MAG logging.