Ultimate branding global footer cannot be saved

Here is steps to recreate the issue:

1.Go to Ultimate branding Custom Footer Content tab
2.Check ALL Footer Contents are blank.
3. Try to save or add something then Save, it will show: cannot be saved.
4. Visit affiliatemarketing.tw/truth/ (with custom domain http://23t.tw/)
Check the footer ,it will show:???? - ????????DIY (Chinese)
this sentence is what I add on Custom Footer Content before but it keep showing up even I delete it.
5. Try to deactivate Ultimate branding, go to http://23t.tw/, ???? - ????????DIY will still show up. Even try to delete Ultimate branding, it will still show up!
6. this happen when I update the plugin to the lastest version, before that it will be deleted as I intent.

Please help me to solve this because my client (http://23t.tw/) didn't like it very much.