There is a defect in the design and manufacture of the barrel assembly. The feed ramp is a separate piece and attached in a way that is known to fail suddenly, causing malfunction.
The picture shows a profile of the PPX barrel after this failure. It remains loosely attached, but moves around as evidenced by the gap between the ramp and its seat.
This happened after less than two-thousand rounds of standard pressure factory ammo.
The warranty replacement is identical, and thus as undependable as the original.
As a range gun, it shot very well, but it was acquired to also be available for home defense. The defect removed our faith in it for that purpose, and since it is a discontinued model, it will never be redesigned to address the problem.
It was traded at an LGS for $175. This included extra mags, Factory holster and mag carrier.
There are many instances of this type of failure on the Walther forum.
Feed ramp issue - WaltherForums