Anaconda scans every disk and flash drive plugged into the system at time of booting a new iso.
I have 5 disks online and the scan takes around 7 minutes. If you have one or two disks, your scan could be about 90 seconds or less, a not-to-long a wait.
If I had my three backup drives (-1,0,+1 versions) plugged, I can go away and return after watching a ballgame.(hours)
The bug is a design decision that needs a workaround.
If I was doing the workaround, I would have anaconda do a quick scan to retrieve the disk-drive-ids (as does "blkid" program.
in a later spoke, where the one or drive(s) I chose are selected, I would do the detailed scan of those one or two drives.
So, now I wait 7 minutes, I select my two drives and I proceed. I first remove all external drives to prevent their being scanned.