It’s because the cluster is set up to expect certain number of airbags. You may have more or less of them.
The cluster needs to be correctly set up using a Tech2 interface or high end. Also can send off to Envyous Customs here in WA who will set it up correctly. All your codes will go once the cluster is set up correctly.
If your car had two airbags, but the cluster came out of a car with 4 airbags, there’s going to be issues.
Also speedo might be out if it came from a V8 and yours is V6.
Fuel gauge can be jiggered if models are mismatched as well.
It’s quite a list.
When i had my Calais cluster installed in my V6 Crewman, Envyous Customs has quite a list of required questions that needed to be answered. I also had to provide my left nut as proof of kms which had to be matched.
It is even possible to have a custom start up logo to replace the Holden one that appears on the screen.