It makes no difference if there is a round in the chamber unless there is a fundamental design flaw. The P320 is apparently a rare case of this.

This is extremely mature technology. People have been churning out defect-free designs for many decades. It is surprising that a company with the engineering experience and pedigree of SIG Sauer would design something with this issue. It would be like if Airbus designed a plane where the wing sometimes fell off mid-flight.