Hi ,
I’ve been having a look into your Navmesh bug and came across something interesting. If you can, please open up a blank level on both 4.3.1 and 4.5 and press “Show FPS”. Are you seeing FPS drop you mentioned there? I believe this may be a general editor drop but if this is not FPS drop you are seeing please let me know so I can continue to try and repro it on my end. Thank you!