XF 1.5 Latest member not updating

hi experts,

I just noticed on my forum the latest registered member is not updating, I'm not using plugin it's the default forum statistics.
I tried to make now a test account on forum and forum still shows the previous registered user,
Any idea what can be the cause please?
Ok now on my forum shows the latest registered user which I made for testing,
Does it take time to show the latest registered user?