I recently had this problem using 4.24
I moved the nav mesh and recast to persistent and this fixed it, however I’m loading levels dynamically so this is not the solution I needed
I deleted the nav mesh and recast, double clicked my landscape level to make sure when I dragged nav in from modes it was properly assigned to that level, many times I would try to move them to this level and the recast wouldn’t cooperate
Then I switched run time generation to dynamic in the recast, and voila it works when loaded \o/ the first time I did this it did not work and that was probably because the recast/nav wasn’t in the correct level