Windows Server 2019 as RDSH. FSLogix configuration:
CleanupInvalidSessions - Recently enabled due to this problem
VHDCompactDisk - Disabled
Profiles
AccessNetworkAsComputerObject - Disabled
ConcurrentUserSessions - Disabled
DeleteLocalProfileWhenVHDShouldApply - Enabled
Enabled - Enabled
GroupPolicyState - Enabled
InstallAppxPackages - Enabled
IsDynamic - Enabled
KeepLocalDir - Disabled
OutlookCachedMode - Disabled
RoamIdentity - Disabled
RoamSearch - Disabled
SizeInMBs - 0x00007530 (30000)
VHDLocations - \\domain\dfs\profiles
VolumeType - VHDX
VolumeWaitTimeMS - 0x00004e20 (20000)
This is clearly not an environment or configuration problem, there have never been any major issues with FSLogix in our environment. Reverting to the previous version immediately solves the problem. This is a bug or problem with this version. I can easily reproduce by rebuilding the server on the old FSLogix version and there are 0 issues. However, if I rebuild the server and install this new version the problem is immediate.
Support really only has the ability to review settings and ensure we are doing everything properly (verify and confirm). Since I already know we are doing everything properly, support in this case can't really help -- only the product team can solve the problem by issuing a hotfix. I understand the requirement to work through support to gather info, but once it is confirmed that the software version is the problem support can't do anything--only the product team can.
I'm glad to have an acknowledgement of the issue and grateful for any assistance. Note that several other folks have indicated the same trouble here, so it's not just me...