This suggested edit appears to have no edit summary whatsoever - the proper HTML source is:
<span class="revision-comment" title="comment on this suggested edit"> </span>
So as you can see by viewing the characters it's the infamous "double space".
How should we deal with this? If the suggestion is good guess it's better to approve it, but should we comment on one of the suggestor's posts asking him nicely to behave? Or something else?
Edit: for those with more than 2K+ rep - this field is mandatory:
So avoiding it is kind of tricking the system.