I don’t have Zedge and I’m having the same issue. After a factory reset, it went from optimizing 1 of 2, to optimizing 1 of 1, but it still takes a full ten minutes to reboot. My text messages also get stuck on sending, GPS sometimes spoofs me somewhere else, and voice to text often won’t work. Now that I’m seeing these issues being voiced by others with ZTE, I think it might be time for a new brand of phone. ZTE Z981 - Build number Z981V1.0.B21