There are following reasons for Sudden drops-
1.- There could be sudden loss of SS like indore coverage problem.
2.- There could be any H/W issue due to which site get fluctuated.
3.- There could be any issue on transmission link, we can check Slip, SES, UAS….. using DTQUP:Dip=all, print.
In case of sudden loss there must be downtime on the cell.