Need some help- Machine not cutting circles but making squares

Hello all.

I have a c-beam based machine that uses phoenix USB controller. I have been using it for few years just fine.
Didnt use it in last few months and yesterday I needed a small part cut for using in my motorcycle. I use openbuilds interface to run gcode. gcode shows circles just fine in 2d view of the software but when machine cuts, it just makes squares (diagonal length of square is matching circle parameter). I checked the $12 value in grbl and is set to 0.00 mm (arc).

What else could be wrong ? machine moves in all direction just fine with manual inputs

 

It is actually -0.00. I don't recall every changing it. Could that be an issue ?

 

I will overwrite that to 0.002 and report back
thx

 

Peter - thanks. That change did the trick. I didn't really such a small change has a big difference. Thanks once again