Larian Studios Forums Divinity: Original Sin 2 Divinity - Original Sin 2 - General ACT 3 SPOILERS: Major Act 3 Death

To avoid Malady scolding you for not doing as you told:

You do initial ritual with Siva (she sends you to seek more training after )

One more after the second source point (where you get source vampirism)

And you have to do one more after the third point, where voidwoken invade the halls of echos, you fight them off and learn of nameless island.

I believe that if you do not do the third one, Malady has to divine the location and die later as a result.

I may be wrong, don't have a save handy to check, unfortunately. But it seems to be the only logical explanation.