However, the reason for these problems isn’t the theory itself, but the way the theory is interpreted - by developers and browsers.

Do you have collaborators who could have generated keys and sold them on their own? DIG's Steam keys and other stores' Steam keys must have some source, after all. Keys don't generate themselves, and only your accounts should be able to request them.This particular game was in Bunch Keys Indie Wizardry Bundle. I assume you had a proper contract for that. Maybe DIG or an intermediary bought 50-200 copies of it?

It isn't stealing because you or an associate must have generated and given them the keys in some way or another?Ideally you would ask a DIG bundle buyer to show you their key for your game, so you can figure out what key request batch it came from, and then you can scratch your head and wonder who you gave those keys to and what journey they took afterwards.