A partition does not scale when the Scale to Fit (/x) or Scale to Target (/stt) option is used.
This can be caused by the partition being much smaller than the original physical drive. Automatic scaling restrictions are enabled by default and prevent the partition from being resized.
Disable the Automatic Scaling Restrictions option in Settings (if using the command line, use the /asr:0 parameter).
When enabled, the Automatic Scaling Restrictions option prevents small partitions from being automatically scaled when restoring or copying a full drive. Partitions with a size of 15GiB or 1/8 the drive size (whichever is less) or smaller will not be scaled when restoring a full drive image or copying a full drive. This provides an automatic method to avoid scaling system reserved, recovery, and utility partitions to larger sizes when upgrading to a larger drive.