Given that no equipment is broken:
If you calculate the power budget (Linkbudget) for up- and downlink carefully you will find in many cases an imbalance. Either the uplink or the downlink is weaker. If the HO due to signal strength is enabled, you can easily see wheter the uplink- or downlink path is weaker – there will be more handover shown in the statistics. If necessary in coverage limited planning scenarios, a tower mounted pre-amplifier can be used to improve the uplink.