I have updated my OnePlus 3 smartphone with a recently released 21MB Oxygen OS 3.2.4 firmware update and it has resolved the automatic restart issue, but brings up a new problem for my device now. Since I have updated the device, I lose the LTE connectivity every now and then. I have tried the manual way as well, but no use. Should I have to wait for the next update or is there any way to revert the software update?
Update: For the time being, I have used this trick and it worked well, solved my problem.
I opened the phone dialer and typed *#*#4636#*#* and went to Phone Information. Now in the Preferred Network section, I have selected the "LTE Only" option. It looks like now my OnePlus 3 locks phone's signal to 4G/LTE.