I think it was be solved.
here are tips:
step.1
open OCLP and go to Settings.
Default Macmini5,3 change it to Macmini5,2 and go to SMBIOS Settings.
step2.
SMBIOS Spoof Model to Macmini5,2 and generate S/N for Macmini5,2.
Step3.
Build and Intstall OpenCore.
Post Install Root Patch.
Re-Test...