Hi Bilal,
The call drop must occur either on the uplink or on the downlink, for one call.
One call can’t drop on both ways at the same time… it is just a matter of detection. Maybe if you slow down the “uplink drop” detection mechanism by one or two seconds, you’ll see mostly “downlink drops” in your cell.
By default, radio parameters are defined in such a way that the uplink is dropped first (coverage is mostly uplink limited, that’s the reason why).