The log in the screenshot [1] is suspicious, that’s why the plugin has included it in there. It is up to the administrator of the website to determine if the event was triggered via a legitimate action or by a person/system trying to exploit a vulnerability.
Considering what I previously mentioned about WordPress deleting drafts automatically, if you agree with my statement there, we could assume that this log is referring to one of those automatic cleanups performed by the website via a scheduled task. A good way to be sure that this is true is to reverse the IP address that you marked as “Unknown IP” and check if the host corresponds to the network that you are using to serve the website.
Here are two tools [2][3] that you can use to execute an IP Lookup.
Here is an example, if you reverse this IP address [4] you will get something like [5] and so you will know that the IP corresponds to Google’s network. The majority of big hosting providers have their own network, others outsource the infrastructure. If you are lucky, you will be able to find enough information using one of these tools to determine the origin of that post deletion action.
Let me know if you need more information.
[1] https://i.imgur.com/Lc0IXXn.jpg
[2] https://mxtoolbox.com/ReverseLookup.aspx
[3] https://remote.12dt.com
[4] 8.8.8.8
— OR — 8.8.4.4
[5] google-public-dns-a.google.com