Hi jaybackintheday,
Like Abraxas (now Mark in Texas), I also think the review you are looking at is an anomaly out of all the many thousands of component latex mattresses that have been sold over the years by SleepEz and other manufacturers that also make component latex mattresses (see post #2 here). It may also have a different “agenda” than just sharing their experience (some companies will post misleading information about their competitors mattresses).
You can read more in post #15 here and the post it links to about loose latex layers and shifting.
Phoenix