What version of Redis you are using, in what kind of Operating System?

2.2, OpenBSD

What is the problem you are experiencing?

http://redis.io/topics/expire says repeated EXPIRE commands have no effect on already volatile keys. They do, they reset the timeout.

What steps will reproduce the problem?

run EXPIRE, wait a bit, run again, repeat. Observe key not expiring.

This was apparently the old behavior and it's changed now, but the documentation doesn't so say. Also, the old behavior was actually useful in some situations; if it's possible to bring it back or emulate it somehow.