I'm not familiar with PRAW specifically, but I ran into an issue a few weeks ago that sounds similar - I started getting 403's on an endpoint (https://www.reddit.com/dev/api/#GET_about_moderators in particular)

I was doing some tinkering to try to figure out why I was only getting 600 requests per 600 seconds based on the rate limiting headers I was seeing, rather than the 1000/600 I expected. I ran into some mentions here that it was related to the tokens being used, oauth/app type/user auth etc.. I don't remember the details at this point, I never figured out a way to see a 1000/600 rate limit no matter what way I configured the token requests.

But what I did run into was that some of the requests I had been making for well over a year now were failing with 403's and it was only after changing the `grant_type` from `password` to `client_credentials`.

So, seeing that you haven't had any feedback here yet - maybe take a look at the token's `grant_type` in your auth flow and see if you can tinker with that to get a different response. (Note, if you're going to use `password` you'll need to pass a `username` and `password` alongside the `grant_type` in the request, presumably that user/pass combo needs to be the one that owns the reddit app.

All of this comes with a disclaimer that I'm using a janky PHP client that hasn't been updated in some time and isn't even remotely close to being as solid as PRAW, so it could be that my client/lib has its own issues in the token/oauth flow and none of this is related, but it's worth a try :D