Hi Peter
Sorry, I'm Japanese and I don't speak well.
I want to confirm user has logon credencial for linkclone/float and it is occured login storme timing, right?
if is it correct, the problem is occured delayed authentication of Horizon environment to ActiveDirectory.
As temporary solution, I suggest you might want to restart every Domain Controller and set restarting to task.
If the problem will not be occured by temp solution, you wiil add few domain controller as parmanent Solution.
