Offset has nothing to do with this, change it back to what it's supposed to be. Once set, offset never changes.
The sovereign remedy for this sort of malfeasant cutting is threefold.
First, using a loupe or magnifying glass or whatever you have handy, inspect the tip of the blade. If the there is even the slightest bit rounded or broken on the tip or, under magnification, the tip doesn't proceed to an infinite point, it dull and should be replaced.
Second, remove the dust cover on the tool carriage and blow out all of the accumulated dust and crud. Pay particular attention to the blade up/down mechanism. It doesn't take much contamination to slow things down just enough to produce this kind of cutting.
Third, remove the blade from the blade holder and with a toothpick or something similar put a tiny bit of silicone grease on the tiny ball bearings where the head of the blade rests. A slow turning blade will also cause this sort of cut.
These three things will clear up this problem 99% of the time. If it doesn't, then check your blade holder to see if there isn't a bit of wear making the blade swivel in a orbit rather than spin dead center in the blade holder.
