Words in new topic title aren't found by search after topic is split

I did a search but didn't find anything. I discovered on our live board today that when I split posts away from a topic to a new topic the words contained in the new topic title don't get found by search unless you then go and edit the content of the first post in the new topic.

Reproduce:
1) Split post to new topic called "Holiday"
2) Search for topics using search term "holiday" - your new topic isn't found unless "holiday" is contained within the post.
3) Edit new topic and change title to "Holiday time" - search doesn't find the topic.
4) Edit the first post of the new topic and add 'Please!" - and search finds the topic using search term of "Holiday"

Comparison:
Create a new topic called "Holiday time - Oh I wish" ... and your new topic is found.

So, the title being given to the new topic in MCP doesn't seem to be sticking, and the topic then being found by search depends on either those key words being contained within the posts which isn't always the case, or a moderator editing the contents of the post to change the md5 per posting.php (so it seems).