For 7 requests in 3 seconds, no, it shouldn’t go down to 792ish. With 800 requests over 60 seconds you’re constantly regaining ratelimit-remaining at a rate of 1 request every 0.075 seconds (60/800). So over 3 seconds you used 7 requests, and regained 40 (but hit your max of 800 so it doesn’t go over that).
As for the requests hitting a 429 when you should have plenty of remaining rate limit, it’s been confirmed as an issue and is being looked at.