Upon much investigation, I have determined this is indeed a bug with the restoration process. As such, I have opened an internal case regarding this issue in order to get this corrected. The case number is #123673 and it will be listed at
http://changelog.cpanel.net/ when resolved.
This issue only affects the restoration of backups which directory names do not match a certain format. I have determined is is still possible to restore this this account via command line by first renaming the directory containing the backup, then proceeding with the restoration of the account. The below commands can be used to accomplish this.
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mv /backupdrive/incremental/accounts/acctname /backupdrive/incremental/accounts/cpmove-acctname
/scripts/restorepkg /backupdrive/incremental/accounts/cpmove-acctname
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