BOLD AI Upsell & Cross‑Sell

Initially I thought this app was good but after using for about 6 months or so I have noticed that somehow some customers are landing on a 'duplicate' item page and when they do this it is shown as a blank page saying 'product is not available' and when they do this they tend to leave the site. I presume the duplicate products must have been picked up by search engines.
When I contacted for help the advice was incomplete and when I queried to ask for further info they still didn't really answer the question. Each time it took a few days to get back. I have disabled this app now as it's doing more harm than good.