When working on my suspension I noticed what looked like a cut in my suspension arm. It is OEM since the steel bush doesn't have any marks on it and there is no indication of any sort of machining on the aluminium either.
Looking at pictures online I cannot find an arm like it.
What is going on?

Attached is a picture. Note the hinge point on the right.

 

Looks like a bad mould? Or it has been in accident?

 

I highly doubt it. It looks factory and intentional. The angle is the same on both sides and there aren't any sign of any type of damage.