Smart Groups with 0 min cache timeouts taking more than 0 minutes to timeout

Sometimes, not sure exactly all the conditions, but smart groups are not refreshing immediately, when the cache timeout is configured to 0 minutes.

The case I found this out in was creating a Smart group for all contacts that have a membership with the status (NEW, CURRENT, GRACE)

Creating a new membership for a user would not immediately show that they are in this smart group.

The strange thing is that its not always the case that this happens, but enough to notice.

PR forthcoming