According to https://appmedia.jp/wizdaphne/78934994
There are two sentry flags on the defeat the guardian of the secret path (necrocore) I just replayed guarda from right at the beginning avoiding every sentry, blocking the LOS of both of of them on zone 2 and 3 when doing the pitfall trap loop to necrocore - beat the necrocore and went up to the the next floor and had the dialogue with lulu about no corrosion. Yet this is my cursed wheel, only one branch.

What am I doing wrong, do any of you have two flags here?