If it was threaded, that would perhaps explain why 15mins may have mitigated the hazard (easy to spot, early indication of onset, probably take a while & several turns to fully loosen).
Thats not to say its acceptable and should not have been fixed ASAP - just that the mitigation, however undesirable, was probably effective. If the check was conducted of course - but the crews were probably keen to ensure the connectors stayed connected.
As you say engines, I'm surprised some form of interim wire locking solution could not have been developed.
DV
I believe that the connector pins used are of the EMI/EMP type. So clearly the DECU is very susceptible to EMI, RFI and EMP.
Is your conclusion that the DECU is susceptible based on the type of connectors used? Designing to avoid EMC problems in an aircraft environment (e.g. through connector choice) is common practice - it doesn't necessarily indicate that there is a known weakness or history of problems with a specific equipment.