Clutch Housing Crack

[GPierce]

I have two clutch housings both with a crack in the same location.
I could not find anything on line about cracks in this location.
Both are cracked from the throw-out-bearing inspection cover outboard and up to the right side.
The picture is upside down.
One is all the way to housing flange the other is shorter. I stop drilled the shorter one and then used dye penetrate to check and see if I got the end of the crack stop drilled.
Are cracks in this location abnormal?