[2022] This Interaction does not make sense, why mirroring a regen stat makes it lose and not degen there is no way to deny this effect in builds like CI (the one I am doing) so I entered a map and to my surprise I died, I tried zealot's oath and vaal pact nothing works because its not regen nor degen.

Lots of stats on Jewellery either can't actually be allowed, or don't actually work, with negative values. In all those cases, we had to set up stats that were a reasonably "reversal" of the core effect to replace the stat if the league mechanic had to reverse those mods.

Regeneration is one of those cases. Regeneration is fundamentally is a form of recovery, and regeneration as a mechanic cannot be given a negative value to cause over-time loss - recovery and loss have to be kept separate internally for a bunch of reasons, many of which relate to keeping characters alive. So keeping the same stats and just setting the values negative would not have worked, and instead we replaced them with the closest equivalent the game can handle, which is over-time loss.

Similarly, added damage can't have negative values because it leads to a bunch of weird edge cases like having maximum damage lower than minimum which intentionally are not allowed and cause the game to spit out errors to show something is wrong and needs fixed, so the added damage mods instead change to adding damage to enemy hits against you.