Ok, Ricko, I think I understand now what you're trying to do. The PIC32MZ is just a slave, and some different MCU is the master. But you're not getting data on the PIC32MZ. I initially wrongly assumed you were sending data out the PIC32MZ and not receiving any return data. For your use case, I really don't have any experience, as I've always used PICs as master devices.
Likewise, most people use PIC MCUs as master devices, and those using them as slave devices are probably just a small fraction compared to master devices. So while there might not be an errata for your situation, it still could be that there's an issue that just hasn't been made public yet. When the PIC32MZ first came out, I recall it taking quite a while for some of the hardware bugs to be publicized.
Are you initializing the SPI port with Harmony, but then using PLIB functions? I've never tried that, but imagine it could be a problem. I have some projects using the PIC32MZ with graphics, and for that there's no choice but to use Harmony, being there's no documentation about how the proprietary graphics work, or their register maps, etc., so I use Harmony for everything. For the other projects I have using the PIC32MZ, which don't use graphics, I don't use Harmony at all. I only use at most PLIB functions, but preferably not even that, but just direct writing to the hardware registers myself.