Normal relays acting like latching relays

I recently installed a Haltech elite 2500 and terminated engine harness on an rb26. The fuel pump and fans trigger as soon as ecu is powered up. multimeter on the dpo channel confirms that the fuel pump should be priming for the set time then shutting off, but the relay in the pre terminated fusebox stays latched on. I have isolated the Engine loom from the rest of the car to simulate a bench test and get the same results. I have also tried a different DPO channel and another relay. Also tried both low and high side triggers. The battery has been relocated to the boot, negative battery terminal and ecu are star point grounded to the engine block, and positive battery terminal goes first to the + starter stud, then to a circuit breaker box that supplies power to all other devices. Could the starter or starter wiring be a possible issue? Vehicle was running with no issues before engine loom and ecu swap, nothing else has been changed. What could cause this to happen, some sort of back feed issue? a bad ground? Thanks in advance

That would usually result from a feedback loop parallel to the relay - if you can post wiring details and the relay/fusebox model it may help identify the issue.