The IO behavior of each Lattice device family could be unique. Some of the device families support pull and bus keeper circuitry for each individual pin, some support such function on a global basis, while others have different pull condition for default.
When moving a working design from one device family to another device family, it is important to check the default IO behavior of the device family in the corresponding data sheet and the related technical notes.
In addition to the unique IO behavior for each device family, the device technology and therefore the performance of the device could vary. For this reason when a working design moves to a different device family, it should go through simulation to verify the functionality and performance against the new device before being downloaded to the hardware.