Mounting Home Folder in AppStream is timing out

We have a system script that runs in an always-on fleet. To fully set up the machine for our users, we need to access data from the Home Folder. This has been mostly working normally, where the script starts and waits for the Home Folder to be mounted (generally takes around 20 seconds) and then the script continues.

For the last couple of months, we've had complaints that the machines aren't being provisioned correctly. Looking at those logs specifically, I can see that the script times out (over 60 seconds) before the Home Folder is mounted. It happens in about 5% of our launches now. How can we make mounting the Home Folder be faster? It shouldn't take that long to mount an S3 path.