Portversion question

[Rem P Roberti]

I have crontab run cvsup, and make a new port index for me nightly.  
This morning I ran portversion -l and found that there was a package it 
regarded as not being up to date.  However, neither portmanager or 
portupgrade picked up the non-current package.  Why would portversion 
indicate a package that is not up to date, and either of the two upgrade 
programs not find it also?

Thanks in advance.

Rem