What is "Last Post" in forum overview

[Jimmi08]

Question

Just some notes about noticed weird behavior:

• you create a new topic, nothing more
• the last post in the forum overview (main page and forum page) is empty (although other topics with posts exist)
• you edit that topic (without replies) and then the Last post displays this topic.

So what is the last post with a topic without replies?
Is it the topic itself or should it only be replies there?

This field:

Thanks

EDIT
maybe it is limited to subforums, the example of 2 topics, both without replies, but the last post is different. As soon as I edit that topic, it will be filled.

[Jimmi08]

@CaMer0n
This is the solution for this. After confirmation, I can create PR.
Note: the correct value of thread replies is another issue.