I have a plane that always starts a rolling circle towards the belly of the first knife edge when rolling with rudder corrections. In other words if I roll left and add top side rudder when at 90 degrees the plane will push to belly. Funny thing is the next knife edge (270 degrees) does not push to belly. In other words, once the plane pushes to belly at 90 degrees into the roll the plane continues on a rolling circle path regardless of how many rolls I do. I have this problem with both left and right rolls. I can of course correct with elevator while passing through the first knife edge potion of the roll but was hoping for a mix to resolve the issue.

I have the rudder -> elevator mix set for knife edge just fine. Also, the plane rolls very axial (i.e., no heading change) if I don't add rudder corrections. Throttle setting seems to make some difference but not a lot (the problem is worse at high throttle settings.) Thrust angles check out fine, incidence is fine, might be a smidge tail heavy. I've double checked to be sure I'm not pushing down elevator when I start the roll... I'm pretty sure I'm not doing that. I figure the smidge tail heavy part could be causing the push to belly at KE if I'm behind the curve a bit on my top side rudder, but why dosen't the second KE push to belly? Any ideas on what is causing this? Thanks.