I noticed this during a flight last evening.Would randomly veer wildly off course and with a little nudge on the yoke it would resume course.

Have not done another flight,but it was in managed mode.

Oh man there are so many problems now.  I have the same behaviors, noticed it on a flight from PHOG to PHLI.  After I took off just randomly started turning even though it was in heading mode.  I had the heading clicked down arrow and set at 020.  It jerked strangely to the right then slowly came back to the left but it still never tracked quite right. Once I got a mile or two out.  It started veering left uncommand.  So I once again gave it a heading to follow of 270 and clicked the down arrow on the heading button again.  It tracked to 270 (it actually stopped 5 degrees short for some reason then kind of weaved back and fourth).  So I clicked NAV as I was about to intercept the flight path line.  Blew right through the flight path but then started turning back towards it, but once it got back on instead of turning left to intercept it just turned tighter and tighter blew though the path and started spiraling towards the ocean.  So I rescued it and hand flew it back to the path.  I put the Airplane directly on the path. Finally after some hunting and searching the NAV route engaged fully.  So I descended to PHLI and was going to do the ILS 35 approach. After NAPUA instead of going to the fix MORKE it decides to start turning left the opposite direction of the runway. So I rescue it again and manually fly to the fix and put it right on the ILS path, even then it has trouble tracking the LOC as it sways back and fourth hunting for the path. 

Then comes a big surprise in the flight dynamics.  For some reason even though I only have 12% fuel. I need a ridiculous amount of thrust to hold 140kts 87 to 95 all the way to the runway. 

To test all of this stuff out again.  I decide to take off from PHLI do a right downwind for 20 miles and then try to intercept the ILS.  As soon as I engage the auto pilot it jerks violently to the right and starts turning right.  I have no flight plan so I don't know why it does this.  even though I have a heading of 350 the plane settles in on a heading of 005 for some reason.  I won't even go into detail about how the airplane has tons of trouble with VS mode and randomly plunging towards the ocean. I turn the HDG mode to 90 click down it tracks to about 85 and then really slowly find 90, it took almost a minute.  Then I set to 170 and it makes it to 170.  Everything went a little better this go round.  Then randomly the plane starts turning right, uncommanded, I have no flight plan.   It just turns and turns and turns until it goes past 45 degrees then starts descending at 5000 fpm and it makes no attempt to right its self other than pulling the throttle back as speed increases.  Until it spirals into the ocean.

The plane has always had a jerky and strange autopilot, but it was usable if you were really careful before SU 14, now it's completely unflyable.

And then the 87%-full throttle just to keep it airborne at 140 kts.  something is super wrong.