Defiler + Card Text Change Effect

Defiler of Instinct

> As an additional cost to cast red permanent spells, you may pay 2 life. **Those spells cost {R} less to cast if you paid life this way. This effect reduces only the amount of red mana you pay.**

if an Effect would replace red with green for example, then the second part would be *Those spells cost {R} less to cast if you paid life this way. This effect reduces only the amount of green mana you pay.*

but because this part should happen after you choose how to play hybrid mana, the R symbol can't reduce the amount of green mana you pay. so the Ability should fail