My zencart install was upgraded from 1.5.5.f to v1.5.6c.

After that the Zen Cart is loading funny. It’s look is different. And when you click on a category the category doesn’t load properly and I can not add new product. It ends up going on the bottom of the category page and the items listed do not show in the store. The toggle buttons are not loading properly.

But if I click on add new product and then when the page comes up to create a new item, clicking on cancel going BACK to the original page, the category/product listing page works properly.

Then I can select the proper category and properly add the new item.

Server runs on PHP Version 7.2.31.

Any help/ideas are appreciated.