I had a tons of errors in vCenter in the recent tasks list when recomposing a pool:

Invalid configuration for device ‘0’
Invalid configuration for device ‘1’

After calls to Vmware support, which they couldn’t pinpoint the error, I sat and watched my VMs being created by composer.

My templates kept showing AppStack vdmks being added during the recompose process, and the pool would fail to publish.

I checked the AppVolumes assignments, and I guess name filtering wasn’t applied correct and was assigning the AppStacks to all the VMs in the OU. ┬áReassigning the AppStack with name filtering turned on resolved the issue.