[Andreas]

Hmm, I think this is a bug.
I've reported it to Jelsoft, but I don't know if it will be fixed in 3.0.x

Here is some code that should correct the behaviour

In functions_subscriptions.php
FIND

PHP Code:

$user = $DB_site->query_first("
    SELECT user.*, subscriptionlog.pusergroupid 


REPLACE that with

PHP Code:

$user = $DB_site->query_first("
    SELECT user.*, subscriptionlog.pusergroupid, subscriptionlog.regdate 


FIND

PHP Code:

if (($sub['nusergroupid'] > 0 AND $user['customtitle'] == 0) OR $reset_title) 


ABOVE that ADD

PHP Code:

// Check if there are active subscriptions that
// - started during this subscription
// - are not finished
// - use the primary usergroup this subscription gives as previous usergroup
// and update their previous usergroup to this subscriptions previous usergroup
if ($sub['nusergroupid'] > 0)
{
    $DB_site->query("UPDATE " . TABLE_PREFIX . "subscriptionlog SET pusergroupid = $user[pusergroupid] WHERE userid = $userid AND pusergroupid = $sub[nusergroupid] AND regdate > $user[regdate] AND status=1");
}