75kva three phase 208v delta to three phase 208v y transformer wiring/results?
The phase order should not matter and should not trip the phases. You've connected the transformer correctly and discarding the neutral on the primary side is fine. Just to be sure, your MEN is not an open or high leg delta? 

The difference in the amp draw can be caused by two things:
- failure in one of the windings 
- unbalance on the primary side

I would suggest to take the following actions:
- run an insulation test on the transformer 
- verify if the unbalance is still within the limits

Also the 7 volts on the neutral will be caused by the phase unbalance.