Horizon 7.2 Reuse computer accounts not being honored

As with all Horizon desktops, there is the occasional problem desktop that needs to be deleted and re-provisioned. Or you have an issue occur somewhere in your infrastructure that causes hundreds of VM's to go offline or lose access to the Horizon connection servers. So you delete the VM's and let Composer do it's thing.

I recently noticed that instead of the VM's being deleted and replaced with the same name, Horizon is going past the maximum pool size and not honoring the "Reuse computer accounts" setting. For example one of our pools has a max size of 400 desktops with a naming convention of name-pat-{n:fixed=3} As one would expect, your names would be 001 through 400. We had a host disconnect and take 40 or so desktops with it, so what did we do when we got the host back up? Delete the 40 that came back in error state and let Horizon re-provision them - standard practice. As they were being built, I noticed the names were going 401, 402, 403... and so on.

I was very confused, did Composer not have enough AD permissions? Nope - the 40 computer accounts that I removed were also deleted in AD.  Did I not check off "reuse computer accounts" on the pool? Nope - checked in Horizon Administrator and it said "Yes" on the pool dashboard, and just to be sure I checked the Guest Customization settings and sure enough, it was checked off there too. So I opened a case with support.

They get back to me to check the "Server Groups" in ADAM to see if the attribute "pae-VmNameReuseAllowed" for the pools is set correctly. Sure enough - it's 0. But why? I begin to check all of my pools for my environment and see that they are all either "<not set>" or "0".

When creating a pool without checking off "Reuse existing computer accounts" it sets the attribute to "<not set>". Checking off the checkbox after creating the pool OR during pool creation, the attribute is "0". In any case - Horizon is not setting the value to "1" when it should. It's a simple fix for small environments if it's needed, but it is still an annoyance.