Use case is to display the products from the same category, which visitor is currently accessing
Criteria Definition used is : Most Viewed Item as Recommendations Key , with Content similarity type
Reason :
When using content similarity with Most Viewed recommendation key , visitors recommended product might change on each refresh of the page.
This happens beacus the most viewed key of the visitor might change with each refresh of the page.
Recommendation :
You should be using Content Similarity with the ‘current Item’ as recommendation criteria in place of Most Viewed key