Cannot unmount volumes after running OLCP app

Below is the output of "diskutil list" after building a USB installer with OpenCore Legacy Patcher.

Unmounting these volumes with:

 sudo diskutil unmountdisk diskN 

reports success, but the volumes remain mounted.

Is this considered normal????

/dev/disk3 (disk image): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme +17.2 GB disk3 1: EFI EFI 209.7 MB disk3s1 2: Apple_HFS Shared Support 16.8 GB disk3s2 /dev/disk4 (disk image): #: TYPE NAME SIZE IDENTIFIER 0: OpenCore Patcher Re... +33.6 GB disk4 /dev/disk5 (external, physical): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *62.0 GB disk5 1: EFI EFI 209.7 MB disk5s1 2: Apple_HFS Install macOS Sequoia 61.7 GB disk5s2 /dev/disk6 (disk image): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme +17.2 GB disk6 1: EFI EFI 209.7 MB disk6s1 2: Apple_HFS Shared Support 16.8 GB disk6s2 /dev/disk8 (disk image): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme +17.2 GB disk8 1: EFI EFI 209.7 MB disk8s1 2: Apple_HFS Shared Support 16.8 GB disk8s2