Is this a bug? IOMMU=rt disables SB

Intel Core i5 7200u
Acer Aspire 5
BIOS Information
Vendor: Insyde Corp.
Version: V2.02

When I use the parameter iommu=rt (grub), secure boots disables itself, although I can still boot. When I remove this and keep only intel_iommu=on, SB is enabled. Is it normal?

At the end you have the event reporter.

Chronologically for what was done:
IOMMU device protection enabled = intel_iommu=on
UEFI SB Enabled → Not found = intel_iommu=on iommu=rt
UEFI SB Not found → Enabled = intel_iommu=on

Sorry for english.

Can you verify using mokutil --sb-state and in the firmware itself?