Stress risers are most significant at corners, welds, connections, etc.
The bigger the change, the more significant the stress riser.
Just as plugging the small end of a spar can significantly increase the allowable load, sealing a cardboard box with tape can make it strong enough to stand on. Don't try that with an open ended box.
Stress risers along the length are pretty much insignificant compared to other items like the standoffs, where the ferrule at the center T ends in the female lower spreader and if the LS is fully seated into the leading edge connector.
Walk around your house and you'll probably see cracks emanating from the corners of void areas like windows, door frames and walkthroughs.
Hope that helps.
Even rounding the edges of your spars a bit will help their life expectancy.
The Infinity comes with plugged ends on the lower spreaders. Pretty cool in a not super high priced kite.