Fixed [1.3.0] Moderator Log - Thread prefix edited from '{old}'

I can't reproduce this. This is a situation that I do quite a lot in the bugs forum, but the old prefix is always shown as "-". This should only happen if there is no "old" key stored in the log.

Was this generated by a standard XF action or an add-on?
 
I can reproduce it:

Select a thread with no prefix
Move threads...
Go
Destination forum: Select forum
Select Apply prefix to selected threads
Select a prefix
Do not leave a redirect
Move Treads
 
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