I've experienced a few bugs so far:
1) Saving mission state very rarely works. Most times I just get a "couldn't save file" message.
2) TrackIR suddenly stops working during a mission. I have to exit the cockpit and re-enter it (Alt-J) in order to continue, but then I have to control the view with the keyboard. When I exit the mission and start another one, TrackIR is back on track (pun intended). ;)
3) When I start the second A-10 campaign mission, LockOn crashes to desktop. The following error information is shown: Appname: LockOn.exe, AppVer: 18.104.22.168, ModName: protect.dll, ModVe