I'm having the same symptoms after upgrading to 3.8.2. PDIP.I is positive (as it's trying to climb), airspeed is well above the FBW min of 12 but the plane (FX-79) dives into the ground just after take-off on Autotune and FBWA. It needs a new airspeed sensor after the crash this morning but will fix, reset parameters and try again. This aircraft has been flying (mostly successfully) for about 6 months until today. There's no physical changes since the last flight apart from upgrading the servo links.
Meanwhile, here's this morning's logs and a few successful autotune flights from July. I don't usually keep the bin files, I just keep a battery and flight log.