Hey @Markmallowman! Welcome to the forums!
Can I ask- you are using a navmesh volume as well as bounds, right? Bounds are an addition to the standard nav volume. It wouldn’t explain why it works when you start in the level with it though…
Try watching this short video to see if it gives you any ideas. Obviously you know at least a bit, it’s surprising how many people don’t know about the “P” shortcut! I don’t know how anyone ever does Nav without it.
Also I found this answer- give it a shot!