Stec 55 hdg failure and ...

I noticed 2 problems during some appraoches the other day.

One was that on takeoff + 500 feet, I pressed HDG but the autopilot did not go after the HDG bug (was about 30 degress to the left fo the lubber line). Ground test b4 runup had all this working ok. I killed the autopilot and re-started and it worked ok then. Any ideas???

Secondly, I was doing a GPS approach in the NAV mode and it seemd to doing a fair job in the 90 degrees turns, but then stated blinking (NAV) and I engaged the HDG to get around the corner. Why is that? Does it let you know whenever in NAV that it can’t take the corner and humbly fails and lets you know?

I love the system, but I don’t understand these 2 problems I am having.

Let me hear from you if you know.