Combust Mercury doesn't act combust?

I heard a Vedic Astrology fact somewhere that even if Mercury is combust from the Sun, it actually can't be combust from the Sun since he has a boon, and that's why he's always 24 degrees from him. Is it true that combust Mercury doesn't act like a combust planet like others do?

I've done ur course and i know about chestbala but still wondering this like even after loosing confidence maybe it doesn't looses it's abilities?