Wrong member listed as last reply

I just noticed tonight that whenever a post shows up as new, the person listed as the last reply (on the page that lists all the topics in a category) isn't the same person as who really did the last reply if you go in and look at the message. In the two cases I've noticed, the last reply name that's showing up is someone who replied earlier in the thread, but newer people have replied since.

Hope that makes sense! If not, please let me know.