I had a 1TB 850 Evo as my cache drive but after experiencing a docker locking the disk up trying to unpack a file, I decided to swap it out with an 512GB 850 Pro and mount the 1TB drive outside the array. 

 

I may not have went about it in the correct way. I added the 512GB drive to the cache pool and let it balance. This worked fine. Once it was done, I moved the 1TB drive out of the pool and ran balance again. When it was done there were too many profiles still for some reason. 90 percent of the data was on the 'single' profile, 10GB or so was on the 'RAID1' profile. So I ran balance 2 more times, the first time it moved the data back to the raid1 profile, the second time I added -dconvert=single. As it sits all the data, is on the single profile, which is fine.

 

The issue is, Unraid reports 1.25TB of free space on a single 512GB drive. Its also doing the same thing with my 1TB drive that's currently outside of the array.  I've restarted the array and rebooted. Any suggestions? 

I've been piddling around with this and I think it has resolved itself.

You just need to wait for the balance to finish.