Magento 1.x Product no longer displays breadcrumbs when added to 2nd root category
I am trying to build a 2nd catalog for a 2nd Website, so I have created a 2nd root category which is not assigned to any website.
However, if I add a product to 2nd root category or any subcategory under that, it breaks the display of that product on Main Website that has Default Category Assigned.
On Main Website, the full Category path no longer displays as though Magento is not sure which category it belongs to.
I have seen this behavior when a product is added to a 2nd subcategory under the same root category i.e. Default Category
But surely this should not happen when the product is added under a completely different root category that is not even assigned to a Website otherwise this means that multi store setups simply cannot have breadcrumbs if products belong to more than one Website (and are under 2 or more different root categories.