Saved MTX Pets not loading upon Import

Dear GGG,

After I've saved my HO with some Pets added by exporting, they always disappear when I try import the same file again, is this a bug?

Everything else in the HO loads fine EXCEPT for the pets. Please see screenshots below which helps demonstrate this.

Exported with Pet:


Import same file, but.....it's gone!


Pets screen - Only one of this pet, not used anywhere else:


I remember this didn't happen a few expansions ago, likely a bug?