When an existing Patron wants to upgrade to another Tier, they need to click on a button which says “Join” to get to the new Tier. This seems wrong to Patrons, as they are already “members”, so they get the impression that they are making a second, new pledge rather than updating their existing pledge.
The “wording” here could be improved.
(The whole edit pledge process seems pretty convoluted, to be honest, but I think this one point has cost us upgrades and support effort.)