When implementing generic DDR interface, it is required that user generate the interface using IPexpress. If not using IPexpress, the user may not implement the DELAYB element to pass the input data through to the IDDRX module. On the LatticeECP2M devices, if the DELAYB element is not used before IDDRX then input data delay value used in the Trace Report will not match the Silicon. causing the differences between results seen in Trace report vs Silicon.
If no data delay is required for a design, then the DEL[3:0] inputs of DELAYB can be set to 0. But DELAYB should always be used for the LatticeECP2M input DDR interfaces.
When IPexpress is used to generate the input DDR interface, it always instantiates the DELAYB module hence the user will not run into this issue.