Kickstart failure with repo from USB

Hello,

I got the problem by launching an kickstart installation with the following boot parameters appended after the vmlinuz:

initrd=initrd.img inst.stage2=hd:LABEL=PROMPTUSBIN inst.ks=hd:LABEL=PROMPTUSBIN:/tsmmirror-rhel8-sda.cfg inst.dd=hd:LABEL=PROMPTUSBIN:/dd-megaraid_sas.rpm inst.repo=hd:LABEL=PROMPTUSBIN:/RHEL/8/BaseOS/x86_64/os inst.gpt net.ifnames=0 biosdevname=0

The only parameter/option failing by Anaconda is always "inst.repo=hd:LABEL=PROMPTUSBIN:/RHEL/8/BaseOS/x86_64/os".
The others worked fine before.
But its done like in the Red Hat documentation (https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/performing_an_advanced_rhel_installation/kickstart-and-advanced-boot-options_installing-rhel-as-an-experienced-user#editing-boot-options_kickstart-and-advanced-boot-options) and Anaconda always says that there aren't any packages.

Does anyone know why or could this be an Anaconda bug?