2 synchronized ups units feeding one load dilema

Hi

A friend of mine had the following issue:

2 parallel synchronized identical 3ph UPS units are feeding on load via a busbar, each UPS is at on end of the busbar and the load is connected at the middle of the busbar,

He is measuring the currents and found out the following

1- the current from each ups is different

2- the current at the ups connection is different from the curretn at the load connection,

I couldn't find a rational explination,

Anyone can?