Hello from czech republic,
i have same problem after last update on BV9500( i didnt found forum for this model,so i writing here, i dont have pro version), phone randomly restarting whole all day, yesterday about 10 times, thats make phone unusable, after every restart i must input pin for sim, so i delete my password temporaly.
its happenig really randomly, its doesnt matter if i work on phone or not, i saw one warning after every restart - simprocessor problem i think it can help for track the problem.
Please focus on that problem, before i never had any problem with phone, i maked factory reset without solve this problem. Somethnig wrong must be in last update, im sure there is no problem with any app