In search results some products show up twice , some disappear

I have problem that when I, for example, enter in product search (that is in header) word “cimd” it’s shows necessary products but after that the problem appears. For example, in the search results there might be some product missing, but at the same time there is product that shows up twice although there are no two identical products. When changing the views (how many products are in one page ) the product that shows up twice and that is missing changes. But the overall amount of product shown is always the same (34 products in this case). What could be the potential fix for this, how could I fix this, so that each product shows up one time and there is no missing product? Added also pictures to show an example of product appearing twice.