Comment 24 for bug 1834875

OK, the sda1 events provide a substantial difference:

--- failing.sda1_event 2019-07-26 10:42:50.424486349 -0400
+++ success.sda1_event 2019-07-26 12:02:54.536766079 -0400
@@ -53,9 +53,16 @@
 ID_FS_VERSION=1.0
 ID_FS_TYPE=ext4
 ID_FS_USAGE=filesystem
+ID_PART_ENTRY_SCHEME=gpt
+ID_PART_ENTRY_UUID=23f70cea-8174-4426-bc82-462217b97245
+ID_PART_ENTRY_TYPE=0fc63daf-8483-4772-8e79-3d69d8477de4
+ID_PART_ENTRY_NUMBER=1
+ID_PART_ENTRY_OFFSET=227328
+ID_PART_ENTRY_SIZE=62689247
+ID_PART_ENTRY_DISK=8:0
 fabric_name=root
 .ID_FS_TYPE_NEW=ext4
 MAJOR=8
 MINOR=1
-DEVLINKS=/dev/disk/by-id/scsi-360022480d7a4872310ff8d8a6789eec9-part1 /dev/disk/cloud/azure_root-part1 /dev/disk/by-id/scsi-14d53465420202020d7a4872310ff41908c3b8d8a6789eec9-part1 /dev/disk/by-uuid/d800ba44-3054-4cb3-81f7-dfe32f5e8b48 /dev/disk/by-label/cloudimg-rootfs /dev/disk/azure/root-part1 /dev/disk/by-id/wwn-0x60022480d7a4872310ff8d8a6789eec9-part1 /dev/disk/by-path/acpi-VMBUS:01-vmbus-00000000000088990000000000000000-lun-0-part1
+DEVLINKS=/dev/disk/by-partuuid/23f70cea-8174-4426-bc82-462217b97245 /dev/disk/by-id/wwn-0x60022480d7a4872310ff8d8a6789eec9-part1 /dev/disk/by-uuid/d800ba44-3054-4cb3-81f7-dfe32f5e8b48 /dev/disk/by-label/cloudimg-rootfs /dev/disk/by-id/scsi-14d53465420202020d7a4872310ff41908c3b8d8a6789eec9-part1 /dev/disk/azure/root-part1 /dev/disk/by-id/scsi-360022480d7a4872310ff8d8a6789eec9-part1 /dev/disk/by-path/acpi-VMBUS:01-vmbus-00000000000088990000000000000000-lun-0-part1 /dev/disk/cloud/azure_root-part1
 TAGS=:systemd:

As we can see here, there are quite a few differences, which appear to reflect what we're seeing: DEVLINKS on the failing instance doesn't include the by-partuuid path, and we're missing all of the ID_PART_ENTRY_* lines from its udev event.

So looks like the next step is probably to determine why the udev event doesn't contain what it should!