What does that mean? Were the other pieces of the mixer checked for length against the line plan? Or were the knots lined up and then “call it good”, creating an unbalanced mixer with shrunk sections, specifically A now being too short.
The thicker lines that take the most load shrink the fastest, btw. The tips are folding because Z is effective too long now due to A shrinking and then B and C tuned to a shrunken A, leaving unshrunken Z way too long.
A quick test is to tie a loop in Z main to shorten about 4-5cm, tune B and C to new Z length, and test fly a few times, making the loop bigger or smaller to lengthen and shorten Z and find where it starts to solve the tip folding.
But this is just compensating for A shrink and really you should remake the mixer to stock lengths of all sections.