Navmesh generation is fully CPU-bound, so the more work your CPU has to perform the later you’ll get your navmesh fully generated. Navmesh generation is using UE4’s generic asynchronous tasks async navmesh generation so it doesn’t get any priority treatment.
BTW, do you really need to generate navmesh on mobile devices? It’s pretty computation-heavy and will suck device’s battery like it’s nobody’s business. Let me know if you need me to tell you how to setup static navmesh.
Cheers,
–mieszko