Hello. I am only guessing, but the notch for the holdopen lever's "foot" is relatively "large" compared to some autoloaders manufactured before it. While this may aid reliability in function, with the slide forward, were this notch not covered by this semicircular area of the slide stop/holdopen lever, it might allow enough grit, etc into the slide rail groove area to cause malfunctions.
Again, this is just my best "guess".
Best.