I recently swapped my motherboard/CPU (so effectively a new machine) and started with a fresh install of DCS, both production and open beta. In both, I've found my game starts with full left rudder depressed if I have the "sync controls on start" checked (which I would prefer to do for other controls). If I tap my pedals, they recenter and everything is fine. So ground starts aren't a big deal. Mid air starts, that's less than ideal.
I had a similar issue in the past and it turned out that DCS had mapped rudder to my MFDs for some reason but that is not the case now. Nothing is visibly mapped to rudder or stick other than the correct items.
I have gone through controls and disabled everything (stick, throttle, trackir, pedals, 2 MFDs, mouse, and keyboard) and this still happens which suggests something is telling DCS rudder is full left on game start that isn't any of those devices which is odd. I went in and calibrated the pedals - which did need a firmware update and fresh calibration - but that did not change anything. Any chance DCS set up the pedals with a bad calibration and maybe a fresh install or a removal/reinstall of the driver for the device would correct it? Again, once I just tap the pedals, they center and everything works exactly as it should. This happens in beta and production with all of the 6 or so planes I own.
Thanks