a little over 1% iirc from Modal’s post Patch 1.2.1 changes to rare/rare MI drop rates (vendor farming is nerfed)
before latest change Vendors, so Vinelton, had much higher double rare chance than enemy drops, so in 1.2.1 vendors got lowered from little over 2% to straight 1%, and bosses got a bit increased to be higher than merchants.
2 Likes