Unregistered torrents (from upgrades to season packs or nuked releases) and the occasional upgrade paths that don’t always work.
My own upgrade paths tend to pull in some versions which get made redundant so every so often, just ensuring there’s no multiple copies as a result of said upgrades
The only entity benefiting in this scenario is Denuvo, while the client clutches their pearls to protect a misguided concept of the elusive lost sale. Denuvo rakes in cash in the name of copy protection, but the truth is most acts of piracy are driven by a lack of means to obtain the product or a desire to demo the product.
Sure it’s their right to protect it but I don’t think there’s any accurate way to actually measure the impact of games with and without such aggressive copy protection.