Hotplugged Flash drive very slow to be recognized

Recently, when I plug in a usb flash drive, it takes over a minute to pop up on KDE's "Disks and Devices" notifier. The same thing happens with Gnome. I've written a bug about this: https://bugzilla.redhat.com/show_bug.cgi?id=1976944 and I've included some log files. In the past, flash drives would be recognized within a few seconds - definitely not anywhere near a minute, so I'd call this a regression. I get the same result both on my desktop and on a laptop, neither of which has much of a load on them. I also see this delay when plugging an SD card into a reader. The journal shows roughly 30,000 messages reporting that one SEQNUM is blocked by another, and I'm wondering if all that traffic is slowing down the recognition of the device. It certainly doesn't seem right that there should be so much meaningless chatter in the log. Is anyone else seeing this sort of behavior? Are there any suggestions as to how to track the problem down? I'm not really familiar with the underlying mechanisms. Steve