Is your LP below 1000? You need to be below 1000 to activate Life Cost 0. And if your LP is below 1000, it is impossible to use Mausoleum as the minimum LP payment is 1000.
the main reason is the skill mentioned "You do not have to spend Life Points to activate a card until your opponent's next turn ends", activate a card effect, but now u pay for tribute summon, so it does not work
Probably there's a difference between paying to use the card effect (Stein's effect) and use a card effect to pay for tribute summon (Mausoleum). I guess when it comes to Mausoleum you are using its effect to pay for tribute summon, you are not paying to activate Mausoleum.
Mausoleum's effect cannot be activated without paying life points, since the effect depends on how much the life points paid. Life cost 0 make you unable to choose how much the life points paid
If "Spell Economics" is active, "Star Blast" cannot be activated without paying Life Points, since the effect depends on the Life Points paid. - maybe this line in wiki make sense for the skill
It's not a bug, this is a situation more similar to the ruling for Star Blast vs Spell Economics mentioned above by another anon.
Mausoleum's effect depends on the amount of LP paid, so you cannot avoid it using Life Cost 0, as the effect cannot be applied otherwise. If you paid 0 LP, you basically do not replace the tribute with any LP.
Anoymous
Anoymous