Export lightmaps to another project

Hello ! We are currently working on various project as a team. As such, we often have to transfer scenes and such from one project to another. However, we have a problem concerning the lightmaps.

When I take my scene, make a package out of it all (lightmaps included) and then export, when I import in the other project, the lightmaps are there, (as in, in the "Lightning" window, they are present and loaded) but they just don't apply on the scene. It's like they aren't here at all.

And so we have to rebake everything, which makes us lose hours of work. (And as the graphic guy, it frustrates me that I have to wait two times)

Any tips on how to deal with this issue ?

Thanks !