Apparently when it fires off too many compilation processes, the machine suffers from what AMD calls a "performance marginality problem".
It appears to only be affecting some Ryzen customers and only those on Linux. It is not an issue with Threadripper and Epyc processors are unaffected.
The numbers are so small that they will be dealing with the problem on a customer-by-customer basis, and its future consumer products will see better Linux testing/validation. It is calling for Ryzen customers believed to be affected by the problem to give AMD Customer Care a bell.
The Ryzen segmentation faults on Linux occur with many, parallel compilation workloads. These are not the workloads most Linux users will be firing off on a frequent basis unless intentionally running scripts like ryzen-test/kill-ryzen.
Generally, Ryzen Linux boxes have been working out when they are not operating under torture. AMD's analysis has also found that these Ryzen segmentation faults aren't isolated to a particular motherboard vendor.