windows 10 - Newly imaged system not recognizing any unallocated space? (smaller image clone to larger drive)

I built a Windows 10 system image in VMWare Workstation that I gave a size of 64GB, so the image could be cloned onto multiple devices of any larger size. I was told that after cloning onto the target machine, I could simply open diskmgmt and refresh and it would pick up the true size of the hard drive. I have cloned this image onto my first target machine but it is not working. Disk Management is not seeing any unallocated space. It shows one EFI partition of 200MB and a C drive of 63.68GB and nothing else. This laptop has a 250GB drive, it should be showing me 186 GB of unallocated space?

EDIT: A workaround "solved" this. I actually shrunk the disk first, by 1024MB, and after that action it suddenly picked up that there was ~170 GB of unallocated space, at which point the C drive could be expanded. But why was this strange workaround necessary?