On my sandbox installation (d16, uc_roles 6.x-2.2, Views 6.x-2.8, VBO 6.x-1.9) nothing happens when I attempt to change role expiration. I get the message:

Performed Set role expirations on user username

but the role is not added, nor is an expiration set if the role was already there.

I've tried it in bulk and one at a time. I've looked through the code and I'm afraid I don't see what might be wrong.

Let me know what I might do to help troubleshoot this.