It is directly passed to tar; please test if GNU tar behaves the same. If so, it's tar behavior, if not, it might be a bug in busybox tar.
Yes, it also happens with GNU Tar.
I am assuming that this claim is made as a result of loading.using me-tv.tcz.
Testing this extension with backup and restore did not result in such claim. Each ld before and after on .gconf,  .gconf/apps,  and .gconf/apps/me-tv remained tc.staff.
No, me-tv folder is just an example...Here it happens always... You can do:
install -d /home/tc/folder/folder2folder  and 
folder2 have 
tc:staff ownership
Edit .filetool.lst and add:
home/tc/folder/folder2Then you go Control Panel->Backup/Restore and backup.
Delete 
folderGo Control Panel->Backup/Restore and restore.
You can see 
folder now has 
root:staff ownership. 
folder2  preserves 
tc:staffI find it interesting that specific directory was added to .filetool.lst when by default home in its entirety is in the backup. Nevertheless even adding specific directory did not produce such claim.
Well, here not...I prefer to put individual items in .filetool.lst so I take away whole 
home from it.
Providing more details that can reproduce this claim would be helpful including file system that is being restored and ls -ld on each directory before and after.
My mydata.tgz is stored in a FAT32 file system.