Short answer: not really — it mostly goes away, but it can come back.
What you’re describing is something a lot of us have seen with badger. The “funk” isn’t just surface smell — it’s natural oils/proteins in the hair. You can reduce it a lot with proper cleaning, but it doesn’t always disappear 100% permanently.
The key thing:

If the brush sits unused, the smell can come back when you re-wet it.
I’ve had the exact same experience:
Brush smells fine after a few uses
Sits for a week or two
First soak again → faint funk is back
It’s basically the hair rehydrating and releasing whatever’s still trapped inside.
In my experience:
Regular use = almost no smell
Long inactivity = chance of it returning
Some knots are just more prone than others
A good deep clean helps a lot, but the real trick is:

use it regularly and dry it properly
If it’s really strong, you can “reset” it with a proper cleaning cycle (dish soap + vinegar, etc.), but even then I’d say most badger brushes never go to absolute zero forever — just to a level you won’t notice in normal use.
So yeah — you’re definitely not alone on this
