The scenario: You have aMember and phpBB talking to each other via the plugin. There are two products with access to different products e.g. Product A – Access to Forum A, Product B – Access to Forum B.
The problem: When someone who is already amember of Product A joins Product B (this can be the other way around too), they are removed from Forum A and can only access Forum B.
Solution: There’s a good chance when setting up the products, you used the default group feature. Setting the default group and no integration on other groups. While that seems logical for aMember, you need to understand that for phpBB a member cannot have two default groups in phpBB (which makes sense).
The solution, set the default group to *no integration* and the other group access to the group for each product.