Comment 5 for bug 1925002

Right, it is related to manual/guided installation.

In manual installation mode the recovery key widget is not displayed but the value is set still, then the code fails to detect the target installation disk because it searches for the value set by partman-auto, which is empty since partitioning is done manually.

The fix for 21.04 is to clear the recovery key if the field is not displayed. It's too late to do the right fix which is to display the recovery key widget even in manual partitioning.
It will be done for 21.10 (cf bug 1925032)