Need Help Understanding Permission Group Changes in the DB

OK So, how best to describe what I'm asking... I run a gaming community, and recently we were provided with private hosting from a game developer that gave my community a few thousand access keys so we could easily white list this privately hosted server. So I created a new XenForo website and I created, just for this server, an application tool. This allows users to login, and fill out applications to join. Then a moderator approves or rejects the application. Because the forum and the application app both use steam logins we added a few lines of code that updates the user's primary user group from registered to approved groups in xenforo's DB.

We tried to accomplish this by updating the user's primary user group in the "xf_user" table, "user_group_id" column. The user group id for registered is 2 and the id for approved is 5. So we updated this entry for the specified user to be 5. (found in table xf_user_group)

When we navigate to the user in the admin panel it correctly shows them in the approved group. But when they user navigates the website they get all kinds of permission errors, and pages/forums they can't access. But if I go via the admin panel, switch that user to another group, then back to approved, there permissions start working again!.

I have tried to compare the database entries for a user that was promoted via my tool, vs a user promoted via the admin panel and I can't find anything, I'm hoping someone would be able to shed some light on this for me!

My goal is to be able to promote all approved members to the approved group via my external app, and not have any permission errors.