When trying to do a Remove-Item on a 8.3 SFN that has both a dot (.) and the second set of characters is 4 length, it fails. We noticed this when a users local cache renamed to USERNAME.XXXX after trying to delete. (where XXX is usually the domain name, ours is 4 characters in length)
Create a folder called "test.test", then try to run in powershell - Remove-Item TEST~1.TES - this will fail everytime. As a workaround you can do - Get-Item TEST~1.TES | Remove-Item
However, more interestly.... if you create a folder called "test.domain" and try to Remove-Item, it will work. But if you create "test.doma", and try it, it will fail. Even though the SFN is the same! "TEST~1.DOM"