Foreword:
Before the P14 patch, I had over 37,000 ODE Infamy, meaning over 150 fort runs, and I only ever saw a C rank displayed.
The times I saw an S rank were runs from other Envoys who invited me and who had told me beforehand that they always get an S.
Rewards for Coga solo runs (P13):
No deaths, all enemies killed
- Fort Curlail 38 ODE Infamy
- Fort Kearnhold 250 ODE Infamy
- (P14) Mirifuir 375 ODE Infamy
My reward is always S despite having a C ranking. I’ve come to accept that it’s just being displayed incorrectly. But there are many people who would find something like this confusing.
What I've tested so far:
- Changing the game language (simple translation error), this didn't help.
- Completing a fort for the first time with a new account: C rating but S reward. (I thought maybe the first completion of the fort is permanently saved, hence the same result every time.)
- Players who always get an S rating get a C rating when I'm the lobby host. And vice versa.
If I have any further findings, I will add them here.
Until then, best regards