Catalog Visibility and Random Error on trying to add item from Catalog

Hello Experts,

I am facing two weird behaviors in the system. It would be great if I get some direction on how to debug. 

1.   For some specific users, when the user is drilling down on the Catalog view under orders, they are not able to see the products defined under the category. I have ensured Price List is tagged to the order and there is no access group associated with either the Catalog or Categories. Now when the user navigates to another subview 'Search' under the Catalog view and comes back to the Catalog view, the products are visible under the categories for the catalog. It's strange but it's happening consistently with those users. If the user logs out and logs back in,