IAM RDS Token Auth only working sometimes

I'm encountered an issue that I've pretty much slammed my head against for a solid day or so. I enabled token based auth for our RDS instances. For testing reasons when I went about enabling I took a snapshot from an already existing db (let's call it db1).

With db1's snapshot I created db2.

Within db2 I created a user for token access and opened proper grants.
I created the IAM reference to that user and db2.
I enabled Token based auth on db2.

When testing this works great. I am able to log in with multiple accounts.

Fast forward to the next day, I go to implement the same steps on db1.
After creating the proper user in the db, after ensuring the db reference maps in IAM
and after enabling token based auth on db1 I cannot connect.

I thought maybe this was specific to the instance so I started to test other devel type DBs and none of them worked.

I decided to make another test instance off of another currently running db's snapshot (let's call it db3).

I created db4 off of that db3 snapshot. Went thru all of the steps and this works.
I am able to log in fine with token based auth.

To conclude, it seems like I can use this token based auth on any new DB I spin up off of a snapshot, but enabling it on current DBs does not work. I have tried a reboot and a stop/start for sanity reasons after enabling to no avail.

I'm pretty stuck at this point and wondering if there is something that's not obvious?