It’s probable that your bike is built right, but that that section of outer cable that links the front triangle with the BB is slightly too short, so when you squish the suspension it is pulling itself out of it’s housing and allowing the inner cable to pull on the mech.
It’s an easy mistake to make because if you do a static setup and measure the cable as you would with other bits you’ll get tit too short. Look at the picture of the blue one above, it shows how much ‘extra’ outer cable you should have, it’s not a direct run between the two stops at all.
As for the design, I really rated mine, which was a 1999 XCR2000, it was a bit heavy, but for the £1000 I paid for it in 2000 it did a brilliant job and lasted a decade before it needed moving on. I’ve not ridden one of the modern ones, but would like to see if the design still makes as much sense as it did. For the sceptics; why do you think the design hasn’t changed in a decade?