I only noticed the curved cut with the last chain, I got at Menards, I think an Oregon. None the chains have been sharpened. But I have filed the bar to remove the burrs.
That's a far cry from:
It always cuts left.
If you have been running dull chains (it sounds as though you have) long enough to cause burrs on the bar, the rails are quite possibly uneven. From the sounds of it, you should let a qualified repair person take care of the problem for you.