I recall an older post with a user having the same problem. When I got into his project file the weirdest thing was the solution to his problem. For some reason it was the Bezier tool was the problem. When I recreated one of the arrows withe the B-Spline instead of the Bezier tool it worked smooth like butter. I have no idea why, I just know that he re-build the other arrows with the B-spline tool and it fixed a jittery arrow problem. Just give it a try and see.
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