Nope. It is most probably caused by operational stress - rudder assembly is moving, fuselage is also working (compression and decompression cycles on take off and landing, thermal expansion and compression). I bet they don't just put red Loctite on it to keep it from getting loose. My bet is design flaws, not manufacturing or QA.

EDIT: I saw the pictures of bolts with pins and bolts without pins. The ones with pins cannot get loose, the others can. Let's see what happened.