Due to a kernel-related issue with the Marvell 88SE6121 SATA controller, currently only trays numbered #3 and #4 work, #1 and #2 do not. Other than that, I've not encountered any bugs in my testing yet.
See:
https://bugzilla.kernel.org/show_bug.cgi?id=216094
https://lore.kernel.org/linux-ide/db6b48b7-d69a-564b-24f0-75fbd6a9e543@noerenberg.de