I've seen this several times already:
Note the timestamps on the two edits, they were submitted at the same time. The 2nd part of the edit often looks like a pointless one, as it did in this case. I probably shouldn't have rejected it.
Tag wikis are made of two parts ....
Part one is the excerpt (which shows up in the hover menu) - it is linked to post 1
Part two is the wiki body (which shows up when you view the wiki) - it is linked to a second post.
When people edit tag wikis they trigger edits on 2 posts. In this particular case there was and edit to the excerpt (titled: libsndfile tag wiki excerpt) and and edit to the wiki body.
Sometimes people do a good job with an excerpt edit and a bad job with the wiki edit. So it is split to allow us the fidelity to accept or reject a part.
All that said, there is certainly a bug in the UI if it is confusing you. How would you clarify this?